The function org-copy-visible should copy visible text only, but it
copies invisible text when there is a link in a header. For example, let
an org buffer contains:

* header 1 [[some link]]
some text
* header 2

After folding the first tree it looks as

* header 1 [[some link]]...
* header 2

After selecting all the headers and doing M-x org-copy-visible (or C-c
C-x v) in the kill-ring we have the text

* header 1 some link
some text
* header 2

But the expected content is

* header 1 some link
* header 2

The function org-copy-visible works as expected when there is
only one header in the region. The bug appears when the region contains
at least two headers.

The dribble file reproducing the bug is attached (recorded right after
'emacs -q').

In GNU Emacs 27.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.27,
cairo version 1.17.4)
 of 2021-03-26 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.12013000
System Description: Arch Linux

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --with-x-toolkit=gtk3 --with-xft --with-wide-int
 --with-modules --with-cairo --with-harfbuzz 'CFLAGS=-march=x86-64
 -mtune=generic -O2 -pipe -fno-plt' CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON
PDUMPER LCMS2 GMP

Important settings:
  value of $LANG: ru_RU.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  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
  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
format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg
epg-config gnus-util rmail rmail-loaddefs text-property-search time-date
subr-x seq byte-opt gv bytecomp byte-compile cconv mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader cl-loaddefs
cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
cyril-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 tab-bar menu-bar
rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core term/tty-colors frame minibuffer 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
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
inotify lcms2 dynamic-setting system-font-setting font-render-setting
cairo move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 47281 10537)
 (symbols 48 6002 1)
 (strings 32 15528 1956)
 (string-bytes 1 507842)
 (vectors 16 10256)
 (vector-slots 8 132881 13054)
 (floats 8 19 41)
 (intervals 56 196 0)
 (buffers 1000 12))

--
Sincerely yours,
M. V. Babushkin