Flipping back to first user's lock screen when logged in as a second user.
Sorry if this is not the right component - I don't know enough about GNOME internals to be sure.
Steps to reproduce:
- Have more than one user configured on the machine.
- Log in as one user, for example the one with UID 1000.
- Click the arrow at the top right, click the user's name then choose "Switch User".
- Choose the other user, for example UID 1001 and log in when prompted.
- The GNOME desktop appears but within a few seconds a lock screen then appears asking for the first user's password.
It is possible to avoid typing in the first user's password by choosing "log in as a different user" and then re-typing the second user's password but then, after the desktop appears, a few seconds later the lock screen for the first user appears again just as before.
There is some more info including a log snippet at: https://bbs.archlinux.org/viewtopic.php?pid=1866087#p1866087