Bug trigger recipe:

In an emacs instance started with emacs -Q load a file containing the
attached file.

give the command M-x toggle-truncate-lines so that truncatinf is ON.

C-u 400 C-f

When the C-n command is issued, the cursor does not remain in the same column.

I attach the bug report buffer content from the emacs instance launched
with emacs -Q

End of recipe.


In GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 2.24.30)
 of 2017-05-17 built on t65
Repository revision: f7c07930b581b1bcfdfb1874b6883233516bdf11
Windowing system distributor 'The X.Org Foundation', version 11.0.11804000
System Description:	Ubuntu 16.04.2 LTS

Recent messages:
Next command uses marks...
Expunging...
Deleted messages expunged.
No messages marked [12 times]
Next command uses marks...
Making completion list...
Bug-Reference mode enabled in current buffer
Making completion list...
user-error: End of history; no default available
delete-backward-char: Text is read-only [8 times]

Configured using:
 'configure --with-mailutils'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GSETTINGS NOTIFY
GNUTLS LIBXML2 FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS GTK2 X11

Important settings:
  value of $LC_MONETARY: it_IT.UTF-8
  value of $LC_NUMERIC: it_IT.UTF-8
  value of $LC_TIME: it_IT.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: SQL[ANSI]

Minor modes in effect:
  bug-reference-mode: t
  global-semanticdb-minor-mode: t
  global-semantic-idle-scheduler-mode: t
  semantic-mode: t
  diff-auto-refine-mode: t
  sml-mode: t
  display-time-mode: t
  global-hi-lock-mode: t
  hi-lock-mode: t
  global-company-mode: t
  company-mode: t
  show-paren-mode: t
  shell-dirtrack-mode: t
  global-pretty-mode: t
  cl-old-struct-compat-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  size-indication-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
/usr/share/emacs/site-lisp/desktop-entry-mode hides /usr/local/share/emacs/site-lisp/desktop-entry-mode
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb hides /usr/local/share/emacs/site-lisp/bbdb
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb-print hides /usr/local/share/emacs/site-lisp/bbdb-print
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb-autoloads hides /usr/local/share/emacs/site-lisp/bbdb-autoloads
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb-vm hides /usr/local/share/emacs/site-lisp/bbdb-vm
/usr/share/emacs/site-lisp/dictionaries-common/flyspell hides /usr/local/share/emacs/site-lisp/flyspell
/home/saint/.emacs.d/elpa/popup-20141002.320/popup hides /usr/local/share/emacs/site-lisp/popup
/home/saint/.emacs.d/elpa/flim-20160311.1537/md5 hides /usr/local/share/emacs/site-lisp/md5
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb-sc hides /usr/local/share/emacs/site-lisp/bbdb-sc
/usr/share/emacs/site-lisp/debian-startup hides /usr/local/share/emacs/site-lisp/debian-startup
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb-gnus hides /usr/local/share/emacs/site-lisp/bbdb-gnus
/usr/share/emacs/site-lisp/cmake-mode hides /usr/local/share/emacs/site-lisp/cmake-mode
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb-snarf hides /usr/local/share/emacs/site-lisp/bbdb-snarf
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb-migrate hides /usr/local/share/emacs/site-lisp/bbdb-migrate
/home/saint/.emacs.d/elpa/bbdb-20151114.1541/bbdb-com hides /usr/local/share/emacs/site-lisp/bbdb-com
/usr/share/emacs/site-lisp/a2ps/a2ps hides /usr/local/share/emacs/site-lisp/a2ps/a2ps
/usr/share/emacs/site-lisp/a2ps/a2ps-print hides /usr/local/share/emacs/site-lisp/a2ps/a2ps-print
/usr/share/emacs/site-lisp/autoconf/autotest-mode hides /usr/local/share/emacs/site-lisp/autoconf/autotest-mode
/usr/share/emacs/site-lisp/dictionaries-common/ispell hides /usr/local/share/emacs/site-lisp/dictionaries-common/ispell
/usr/share/emacs/site-lisp/dictionaries-common/flyspell hides /usr/local/share/emacs/site-lisp/dictionaries-common/flyspell
/usr/share/emacs/site-lisp/dictionaries-common/debian-ispell hides /usr/local/share/emacs/site-lisp/dictionaries-common/debian-ispell
/usr/local/share/emacs/site-lisp/scala-mode-feature hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-feature
/usr/local/share/emacs/site-lisp/scala-mode-feature-speedbar hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-feature-speedbar
/usr/local/share/emacs/site-lisp/scala-mode-auto hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-auto
/usr/local/share/emacs/site-lisp/scala-mode hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode
/usr/local/share/emacs/site-lisp/scala-mode-navigation hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-navigation
/usr/local/share/emacs/site-lisp/scala-mode-feature-tags hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-feature-tags
/usr/local/share/emacs/site-lisp/scala-mode-fontlock hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-fontlock
/usr/local/share/emacs/site-lisp/scala-mode-lib hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-lib
/usr/local/share/emacs/site-lisp/scala-mode-variables hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-variables
/usr/local/share/emacs/site-lisp/scala-mode-ui hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-ui
/usr/local/share/emacs/site-lisp/scala-mode-feature-electric hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-feature-electric
/usr/local/share/emacs/site-lisp/scala-mode-constants hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-constants
/usr/local/share/emacs/site-lisp/scala-mode-indent hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-indent
/usr/local/share/emacs/site-lisp/scala-mode-inf hides /usr/local/share/emacs/site-lisp/scala-mode/scala-mode-inf
/usr/local/share/emacs/site-lisp/u-vm-color hides /usr/local/share/emacs/site-lisp/vm/lisp/u-vm-color
/usr/local/share/emacs/site-lisp/tapestry hides /usr/local/share/emacs/site-lisp/vm/lisp/tapestry
/usr/local/share/emacs/site-lisp/emacs-goodies-el/wdired hides /usr/local/share/emacs/26.0.50/lisp/wdired
/usr/local/share/emacs/site-lisp/emacs-goodies-el/ibuffer hides /usr/local/share/emacs/26.0.50/lisp/ibuffer
/home/saint/.emacs.d/elpa/flim-20160311.1537/hex-util hides /usr/local/share/emacs/26.0.50/lisp/hex-util
/usr/local/share/emacs/site-lisp/dom hides /usr/local/share/emacs/26.0.50/lisp/dom
/home/saint/.emacs.d/elpa/flim-20160311.1537/md4 hides /usr/local/share/emacs/26.0.50/lisp/md4
/usr/local/share/emacs/site-lisp/emacs-goodies-el/ido hides /usr/local/share/emacs/26.0.50/lisp/ido
/usr/share/emacs/site-lisp/dictionaries-common/flyspell hides /usr/local/share/emacs/26.0.50/lisp/textmodes/flyspell
/usr/share/emacs/site-lisp/dictionaries-common/ispell hides /usr/local/share/emacs/26.0.50/lisp/textmodes/ispell
/usr/local/share/emacs/site-lisp/css-mode hides /usr/local/share/emacs/26.0.50/lisp/textmodes/css-mode
/usr/share/emacs/site-lisp/rst hides /usr/local/share/emacs/26.0.50/lisp/textmodes/rst
/usr/local/share/emacs/site-lisp/emacs-goodies-el/table hides /usr/local/share/emacs/26.0.50/lisp/textmodes/table
/usr/local/share/emacs/site-lisp/emacs-goodies-el/cfengine hides /usr/local/share/emacs/26.0.50/lisp/progmodes/cfengine
/usr/local/share/emacs/site-lisp/nxml/rng-cmpct hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-cmpct
/usr/local/share/emacs/site-lisp/nxml/xsd-regexp hides /usr/local/share/emacs/26.0.50/lisp/nxml/xsd-regexp
/usr/local/share/emacs/site-lisp/nxml/nxml-mode hides /usr/local/share/emacs/26.0.50/lisp/nxml/nxml-mode
/usr/local/share/emacs/site-lisp/nxml/nxml-rap hides /usr/local/share/emacs/26.0.50/lisp/nxml/nxml-rap
/usr/local/share/emacs/site-lisp/nxml/rng-nxml hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-nxml
/usr/local/share/emacs/site-lisp/nxml/nxml-util hides /usr/local/share/emacs/26.0.50/lisp/nxml/nxml-util
/usr/local/share/emacs/site-lisp/nxml/xmltok hides /usr/local/share/emacs/26.0.50/lisp/nxml/xmltok
/usr/local/share/emacs/site-lisp/nxml/rng-parse hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-parse
/usr/local/share/emacs/site-lisp/nxml/rng-valid hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-valid
/usr/local/share/emacs/site-lisp/nxml/rng-util hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-util
/usr/local/share/emacs/site-lisp/nxml/rng-dt hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-dt
/usr/local/share/emacs/site-lisp/nxml/nxml-parse hides /usr/local/share/emacs/26.0.50/lisp/nxml/nxml-parse
/usr/local/share/emacs/site-lisp/nxml/rng-xsd hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-xsd
/usr/local/share/emacs/site-lisp/nxml/nxml-enc hides /usr/local/share/emacs/26.0.50/lisp/nxml/nxml-enc
/usr/local/share/emacs/site-lisp/nxml/nxml-ns hides /usr/local/share/emacs/26.0.50/lisp/nxml/nxml-ns
/usr/local/share/emacs/site-lisp/nxml/rng-pttrn hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-pttrn
/usr/local/share/emacs/site-lisp/nxml/nxml-maint hides /usr/local/share/emacs/26.0.50/lisp/nxml/nxml-maint
/usr/local/share/emacs/site-lisp/nxml/rng-uri hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-uri
/usr/local/share/emacs/site-lisp/nxml/rng-maint hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-maint
/usr/local/share/emacs/site-lisp/nxml/rng-match hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-match
/usr/local/share/emacs/site-lisp/nxml/nxml-outln hides /usr/local/share/emacs/26.0.50/lisp/nxml/nxml-outln
/usr/local/share/emacs/site-lisp/nxml/rng-loc hides /usr/local/share/emacs/26.0.50/lisp/nxml/rng-loc
/usr/local/share/emacs/site-lisp/emacs-goodies-el/newsticker hides /usr/local/share/emacs/26.0.50/lisp/net/newsticker
/usr/local/share/emacs/site-lisp/socks hides /usr/local/share/emacs/26.0.50/lisp/net/socks
/home/saint/.emacs.d/elpa/flim-20160311.1537/sasl hides /usr/local/share/emacs/26.0.50/lisp/net/sasl
/home/saint/.emacs.d/elpa/flim-20160311.1537/hmac-def hides /usr/local/share/emacs/26.0.50/lisp/net/hmac-def
/home/saint/.emacs.d/elpa/flim-20160311.1537/ntlm hides /usr/local/share/emacs/26.0.50/lisp/net/ntlm
/home/saint/.emacs.d/elpa/flim-20160311.1537/hmac-md5 hides /usr/local/share/emacs/26.0.50/lisp/net/hmac-md5
/home/saint/.emacs.d/elpa/flim-20160311.1537/sasl-cram hides /usr/local/share/emacs/26.0.50/lisp/net/sasl-cram
/home/saint/.emacs.d/elpa/flim-20160311.1537/sasl-ntlm hides /usr/local/share/emacs/26.0.50/lisp/net/sasl-ntlm
/home/saint/.emacs.d/elpa/flim-20160311.1537/sasl-digest hides /usr/local/share/emacs/26.0.50/lisp/net/sasl-digest
/usr/local/share/emacs/site-lisp/emms/tq hides /usr/local/share/emacs/26.0.50/lisp/emacs-lisp/tq

Features:
(shadow sort emacsbug bug-reference semantic/edit semantic/tag-write
semantic/decorate/mode semantic/dep semantic/tag-file semantic/db-find
semantic/db-ref semantic/db-mode semantic/wisent/java-tags
semantic/wisent/javat-wy semantic/wisent semantic/wisent/wisent
jdee-plugins jdee jdee-wiz jdee-refactor dired-aux jdee-project-file
jdee-jdk-manager jdee-jdb jdee-java-grammar jdee-which-method
jdee-font-lock jdee-help jdee-gen jdee-custom jdee-compile jdee-class
jdee-file-util jdee-bytecode jdee-bsh jdee-parse-expr jdee-bug jdee-run
jdee-dbs jdee-dbo jdee-widgets tree-widget jdee-db jdee-open-source
semantic/senator semantic/decorate pulse jdee-util jdee-import
jdee-complete semantic/idle jdee-parse rx jdee-imenu semantic/imenu
semantic/sb semantic/sort semantic/db-file data-debug cedet-files
semantic/db eieio-base semantic/java semantic/format semantic/tag-ls
semantic/find semantic/doc semantic/ctxt semantic/util-modes
semantic/util semantic semantic/tag semantic/lex semantic/fw mode-local
avl-tree jdee-annotations efc cedet beanshell eieio-compat ediff-merg
ediff-wind ediff-diff ediff-mult ediff-help ediff-init ediff-util ediff
ensime-company yasnippet scala-mode2 scala-mode2-sbt scala-mode2-map
scala-mode2-fontlock scala-mode2-indent scala-mode2-paragraph
scala-mode2-lib mpuz jka-compr rect warnings debug sh-script smie
eieio-opt find-func dabbrev cl-extra bbdb-snarf vm-edit vm-thread color
help-fns radix-tree web-mode disp-table html-mode jsp-html-helper-mode
asp-html-helper-mode php-html-helper-mode html-helper-mode tempo
lisp-mnt mm-archive network-stream url-http tls gnutls nsm url-cache
url-auth url url-proxy url-privacy url-expand url-methods url-history
url-cookie url-domsuf url-util mailcap vc-git misearch multi-isearch
vm-sort mail-extr mailalias flyspell ispell quail help-mode vm-reply
vm-mark vm-delete u-vm-color longlines vm-save tapestry vm-crypto
vm-imap vm-rfaddons vm-menu vm-window vm-toolbar vm-mime vm-undo
vm-summary-faces vm-summary vm-mouse vm-page vm-motion vm-minibuf
vm-message vm-macro linum ensime ensime-sbt sbt-mode sbt-mode-rgrep grep
sbt-mode-comint sbt-mode-buffer sbt-mode-project ensime-http ensime-ui
ensime-semantic-highlight ensime-doc ensime-search ensime-undo
ensime-startup ensime-refactor diff-mode ensime-popup ensime-notes
ensime-model ensime-mode ensime-inspector ensime-goto-testfile
ensime-editor popup ensime-debug gdb-mi bindat gud ensime-stacktrace
ensime-inf ensime-completion-util scala-mode2-syntax ensime-config
ensime-util ensime-client ensime-vars s flymake compile pp arc-mode
archive-mode dash url-gw ensime-macros nxml-mode nxml-outln nxml-rap
nxml-util nxml-glyph xmltok hideshow help-at-pt bbdb-com crm bbdb
bbdb-site timezone supercite easy-mmode regi edit-server time message
subr-x puny dired dired-loaddefs rfc822 mml mml-sec epa derived epg
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader mmm-mode mmm-univ mmm-class mmm-region mmm-auto mmm-vars
mmm-utils mmm-compat ps-print ps-print-loaddefs ps-def lpr eudcb-ldap
ldap eudc eudc-options-file eudc-vars saint-theme gnus nnheader
gnus-util rmail rmail-loaddefs hl-line hi-lock server nxml-enc
hippie-exp js sgml-mode dom xml json map imenu company-files
company-oddmuse company-keywords company-etags etags xref project
company-gtags company-dabbrev-code company-dabbrev company-capf
company-cmake company-ropemacs company-xcode company-clang
company-semantic company-eclim company-template company-css company-nxml
company-bbdb company avoid pascal cc-mode cc-fonts cc-guess cc-menus
cc-cmds cc-styles cc-align cc-engine paren starttls speedbar sb-image
ezimage dframe spook cookie1 conf-mode sql view saintlib face-remap
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
vm-virtual vm-folder vm-misc vm-autoloads vm-vars vm-version vm fortune
finder-inf charmap cider-autoloads clojure-mode-autoloads edmacro kmacro
pkg-info-autoloads epl-autoloads info package epg-config url-handlers
url-parse url-vars seq tramp tramp-compat tramp-loaddefs trampver
ucs-normalize parse-time format-spec advice auth-source cl-seq eieio
byte-opt bytecomp byte-compile cconv eieio-core cl-macs eieio-loaddefs
password-cache ess-toolbar ess-mous mouseme thingatpt browse-url
ess-menu ess-swv ess-noweb noweb-font-lock-mode essl-bug essd-omg
essl-omg essd-els essd-sas essl-sas essa-sas executable shell pcomplete
essd-arc essd-vst essd-xls essl-lsp essd-sta essl-sta cc-vars cc-defs
make-regexp essd-sp6 essd-sp5 essd-sp3 essd-r essl-s ess-inf ess-utils
comint ansi-color ring ess-mode noweb-mode ess ess-cust ess-emcs
ess-site pretty-mode cl gv mairix cus-edit easymenu cus-start cus-load
wid-edit cl-loaddefs cl-lib time-date mule-util tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote dbusbind inotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 1580054 201510)
 (symbols 48 102665 81)
 (miscs 40 67765 6946)
 (strings 32 466361 171402)
 (string-bytes 1 10983531)
 (vectors 16 179112)
 (vector-slots 8 3441678 215525)
 (floats 8 587 2185)
 (intervals 56 135879 4204)
 (buffers 976 107)
 (heap 1024 162047 35574))

-- 
ing. Gian Uberto Lauri
Senior Solution Developer
Dir. Tecnica Innovazione Ricerca / Tech. Innovation & Research Div.
GianUberto.Lauri@eng.it

Sun Java Certified Programmer

Engineering Ingegneria Informatica spa
Corso Stati Uniti 23/C, 35127 Padova (PD)

Tel. +39-049.8283.526         | main(){printf(&unix["\021%six\012\0"],
Fax  +39-049.8283.569		  |    (unix)["have"]+"fun"-0x60);}
http://www.eng.it          	  |          David Korn, AT&T Bell Labs
                  			  |          ioccc best One Liner, 1987