Actions that triggered the bug:


M-x edit-abbrevs


Enter abbrevs in fundamental or global abbreviations at bottom of the list, e.g.:


"dfn" 0 "definition"


C-c C-c


Buffer appears committed (modified flag disappears). Close buffer, test the abbrev in "abbrev-mode" minor mode and nothing happens. M-x edit-abbrevs again. The definition I entered is no longer there. This is in the same session. Emacs was not closed/reopened. The definitions are not applying/temporarily saving.


In GNU Emacs 26.3 (build 1, x86_64-pc-cygwin)
of 2019-08-31 built on moufang2
Repository revision: 522486e90a3d9402d836c2186be9e73299423cd9
Windowing system distributor 'Microsoft Corp.', version 10.0.19041
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Quit
(New file)
Making completion list...
Abbrev mode enabled in current buffer
Saving all Org buffers... done


Configured using:
'configure
--srcdir=/home/kbrown/src/cygpackages/emacs/emacs-26.3-2.x86_64/src/emacs-26.3
--prefix=/usr --exec-prefix=/usr --localstatedir=/var --sysconfdir=/etc
--docdir=/usr/share/doc/emacs --htmldir=/usr/share/doc/emacs/html -C
--with-w32 'CFLAGS=-ggdb -O2 -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -fstack-protector-strong
--param=ssp-buffer-size=4
-fdebug-prefix-map=/home/kbrown/src/cygpackages/emacs/emacs-26.3-2.x86_64/build=/usr/src/debug/emacs-26.3-2
-fdebug-prefix-map=/home/kbrown/src/cygpackages/emacs/emacs-26.3-2.x86_64/src/emacs-26.3=/usr/src/debug/emacs-26.3-2'
CPPFLAGS= LDFLAGS='


Configured features:
XPM JPEG TIFF GIF PNG IMAGEMAGICK SOUND DBUS GLIB NOTIFY ACL GNUTLS
LIBXML2 ZLIB TOOLKIT_SCROLL_BARS XIM THREADS LCMS2


Important settings:
locale-coding-system: nil


Major mode: Info


Minor modes in effect:
global-auto-revert-mode: t
tooltip-mode: t
global-eldoc-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-mode: t
menu-bar-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
buffer-read-only: t
line-number-mode: t
transient-mark-mode: t


Load-path shadows:
None found.


Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg gnus-util rmail rmail-loaddefs
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils jka-compr info elec-pair org-element avl-tree generator org
org-macro org-footnote org-pcomplete pcomplete org-list org-faces
org-entities noutline outline easy-mmode org-version ob-emacs-lisp ob
ob-tangle org-src ob-ref ob-lob ob-table ob-keys ob-exp ob-comint comint
ansi-color ring ob-core ob-eval org-compat org-macs org-loaddefs
format-spec find-func cal-menu calendar cal-loaddefs edmacro kmacro
advice autorevert filenotify arjen-theme finder-inf package easymenu
epg-config url-handlers url-parse auth-source cl-seq eieio eieio-core
cl-macs eieio-loaddefs password-cache url-vars seq byte-opt gv bytecomp
byte-compile cconv cl-loaddefs cl-lib time-date mule-util tooltip eldoc
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel disp-table
term/w32-win w32-win w32-vars term/common-win 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 threads dbusbind gfilenotify w32 lcms2 multi-tty
make-network-process emacs)


Memory information:
((conses 16 165726 13709)
(symbols 48 27132 1)
(miscs 40 72 220)
(strings 32 55598 1442)
(string-bytes 1 1610203)
(vectors 16 22900)
(vector-slots 8 589906 9136)
(floats 8 97 210)
(intervals 56 320 176)
(buffers 992 16))

Brett