I was for a long time confused why LibreOffice always showed my the window to restore documents "after a crash", when I had no memory of LibreOffice crashing. Turns out if I choose to log-out or shutdown the pc, instead of asking me if it should save the open files, LibreOffice just quits. Other native applications like gedit throw up a dialog correctly. This only happens when LibreOffice is quitted coming through a reboot or log-out request. When I close the window with the close icon, it asks correctly what to do. Debian Bullseye, Gnome interface.
It'll be fixed from next LO release 7.6.0 version *** This bug has been marked as a duplicate of bug 142176 ***