Hello,

I find this regression from emacs 26.1. It can be very easily reproduced in
emacs -Q:

1. emacs -Q
2. Press C-q C-l in the scratch buffer (this will insert the  ^L character)
3. Now hit RET, that character will go away.
3-alternative: Select a region that contains that ^L char and do C-M-\
(indent-region). That char will get deleted again.

This regression is evident in all my emacs-lisp packages, because the ^L
chars used to separate the sections disappear when I auto-indent the whole
package.

In GNU Emacs 27.0.50 (build 7, x86_64-pc-linux-gnu, GTK+ Version 2.24.23)
 of 2018-07-16
Repository revision: 46d7c786324f98e73b7615fbc9515ce9a14fa5d4
Windowing system distributor 'The X.Org Foundation', version 11.0.60900000
System Description: Red Hat Enterprise Linux Workstation release 6.8
(Santiago)

Configured using:
 'configure --with-modules
 --prefix=/home/kmodi/usr_local/apps/6/emacs/master
 '--program-transform-name=s/^ctags$/ctags_emacs/'
 --enable-checking=yes,glyphs --enable-check-lisp-object-type
 'CPPFLAGS=-I/home/kmodi/usr_local/6/include -I/usr/include/freetype2
 -I/usr/include' 'CFLAGS=-ggdb3 -O0' 'CXXFLAGS=-ggdb3 -O0'
 'LDFLAGS=-L/home/kmodi/usr_local/6/lib -L/home/kmodi/usr_local/6/lib64
 -ggdb3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY
ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK2 X11 MODULES THREADS

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix

-- 

Kaushal Modi