Subject: 26.3; refill-mode doesn't allow me to add text at the end of a paragraph

From: David Klein <[email-masked]>
Date: Tue, 8 Dec 2020 10:16:40 +0200

--text follows this line--

runemacs.exe -Q
(setq auto-mode-alist
      (cons '("\\.latex$" . latex-mode) auto-mode-alist))^X^E
(add-hook 'latex-mode-hook 'refill-mode)^X^E
^X^F junk.latex
Type in a few random lines interspersed with empty lines
Go back to the end of a line that is followed by an empty line and type
a space (or several). No space gets inserted. Non whitespace inserts
correctly.

In GNU Emacs 26.3 (build 1, x86_64-w64-mingw32)
 of 2019-08-29 built on CIRROCUMULUS
Repository revision: 96dd0196c28bc36779584e47fffcca433c9309cd
Windowing system distributor 'Microsoft Corp.', version 10.0.19041
Recent messages:
Checking 34 files in c:/emacs-26.3-x86_64/share/emacs/26.3/lisp/emulation...
Checking 176 files in
c:/emacs-26.3-x86_64/share/emacs/26.3/lisp/emacs-lisp...
Checking 24 files in c:/emacs-26.3-x86_64/share/emacs/26.3/lisp/cedet...
Checking 57 files in c:/emacs-26.3-x86_64/share/emacs/26.3/lisp/calendar...
Checking 87 files in c:/emacs-26.3-x86_64/share/emacs/26.3/lisp/calc...
Checking 105 files in c:/emacs-26.3-x86_64/share/emacs/26.3/lisp/obsolete...
Checking for load-path shadows...done
Mark set
Saved text from "From: [email-masked]"
Making completion list...

Configured using:
 'configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS THREADS LCMS2

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252

Major mode: LaTeX

Minor modes in effect:
  refill-mode: t
  shell-dirtrack-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
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(help-mode pp shadow sort mail-extr emacsbug message rmc puny seq
byte-opt gv bytecomp byte-compile cconv cl-loaddefs cl-lib dired
dired-loaddefs format-spec rfc822 mml easymenu mml-sec password-cache
epa derived epg epg-config 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 refill
easy-mmode tex-mode compile shell pcomplete comint ansi-color ring
elec-pair time-date mule-util tooltip eldoc electric uniquify ediff-hook
vc-hooks lisp-float-type mwheel dos-w32 ls-lisp 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 w32notify w32 lcms2 multi-tty make-network-process
emacs)

Memory information:
((conses 16 111645 12010)
 (symbols 48 21266 1)
 (miscs 40 65 262)
 (strings 32 33582 1324)
 (string-bytes 1 893823)
 (vectors 16 16065)
 (vector-slots 8 514669 13810)
 (floats 8 61 267)
 (intervals 56 379 30)
 (buffers 992 14))