Load the following code block:

    (defun test ()
      (interactive)
      (print this-command)
      (read-from-minibuffer "test")
      (print this-command))

Now run M-x test.

The first print prints correctly "test" while the second print prints
"exit-minibuffer"
The docstring of the `this-command` variable says: "The command now
being executed." I would think the command "exit-minibuffer" should have
been completed here, so the current command being executed for the
second print, i.e. the value of the `this-command` variable,  should again
be "test".


In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.23,
cairo version 1.16.0)
of 2020-12-21 built on daniel-Ubuntu
Repository revision: faf3613cba8571eaef2709bd7bb6f11a956b9262
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12009000
System Description: Ubuntu 20.10

Configured using:
'configure --with-imagemagick --with-cairo --with-modules'

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

Important settings:
  value of $LC_MONETARY: nl_NL.UTF-8
  value of $LC_NUMERIC: nl_NL.UTF-8
  value of $LC_TIME: nl_NL.UTF-8
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Message

Minor modes in effect:
  mml-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
  auto-fill-function: message-do-auto-fill
  transient-mark-mode: t
  abbrev-mode: t

Load-path shadows:
None found.

Features:
(cus-edit cus-start cus-load wid-edit mailalias mailclient pp shadow
sort mail-extr emacsbug message rmc puny dired dired-loaddefs rfc822 mml
mml-sec epa derived epg epg-config gnus-util rmail rmail-loaddefs
text-property-search time-date mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils help-fns radix-tree cl-print
debug backtrace help-mode find-func .emacs finder-inf info package
easymenu browse-url url url-proxy url-privacy url-expand url-methods
url-history url-cookie url-domsuf url-util mailcap url-handlers
url-parse auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache json subr-x map url-vars seq byte-opt gv bytecomp
byte-compile cconv cl-loaddefs cl-lib iso-transl 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 button
loaddefs faces cus-face macroexp files window 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 237418 22864)
(symbols 48 15091 0)
(strings 32 75289 3389)
(string-bytes 1 1916083)
(vectors 16 22714)
(vector-slots 8 306359 25686)
(floats 8 41 58)
(intervals 56 1029 11)
(buffers 984 16))