lock screen: Clicking on icon to log in as other user unlocks the screen

Using Debian sid/unstable with GNOME Shell 3.38.1 and GDM 3.38.2, we have one user with auto login enabled, where locking the screen and then clicking the icon with two people in it in the bottom right corner, unlocks the screen.

The issue happened on November 30th, 2020 at 12:02:

$ journalctl -b -1 -u gdm
-- Logs begin at Sat 2020-06-06 00:10:39 CEST, end at Tue 2020-12-01 12:09:58 CET. --
Nov 29 22:43:56 morley systemd[1]: Starting GNOME Display Manager...
Nov 29 22:43:56 morley systemd[1]: Started GNOME Display Manager.
Nov 29 22:43:56 morley gdm-autologin][1298]: gkr-pam: no password is available for user
Nov 29 22:43:56 morley gdm-autologin][1298]: pam_unix(gdm-autologin:session): session opened for user molgenuser by (uid=0)
Nov 29 22:43:56 morley gdm-autologin][1298]: gkr-pam: gnome-keyring-daemon started properly
Nov 29 22:43:57 morley gdm-autologin][1298]: pam_unix(gdm-autologin:session): session closed for user molgenuser
Nov 29 22:43:57 morley gdm3[1293]: Gdm: GdmDisplay: Session never registered, failing
Nov 29 22:43:57 morley gdm-launch-environment][1551]: pam_unix(gdm-launch-environment:session): session opened for user Debian-gdm by (uid=0)
Nov 29 22:44:08 morley gdm-password][2024]: gkr-pam: unable to locate daemon control file
Nov 29 22:44:08 morley gdm-password][2024]: gkr-pam: stashed password to try later in open session
Nov 29 22:44:08 morley gdm-password][2024]: pam_unix(gdm-password:session): session opened for user molgenuser by (uid=0)
Nov 29 22:44:08 morley gdm-password][2024]: gkr-pam: gnome-keyring-daemon started properly and unlocked keyring
Nov 29 22:44:11 morley gdm3[1293]: Gdm: Child process -1628 was already dead.
Nov 30 12:02:21 morley gdm-autologin][20172]: gkr-pam: no password is available for user
Nov 30 12:02:21 morley gdm-autologin][20172]: pam_unix(gdm-autologin:session): session opened for user molgenuser by (uid=0)
Nov 30 12:02:21 morley gdm-autologin][20172]: gkr-pam: couldn't unlock the login keyring.
Nov 30 12:05:47 morley gdm-autologin][20449]: gkr-pam: no password is available for user
Nov 30 12:05:47 morley gdm-autologin][20449]: pam_unix(gdm-autologin:session): session opened for user molgenuser by (uid=0)
Nov 30 12:05:47 morley gdm-autologin][20449]: gkr-pam: couldn't unlock the login keyring.
Dec 01 11:05:46 morley systemd[1]: Stopping GNOME Display Manager...
Dec 01 11:05:46 morley gdm3[1293]: Gdm: Freeing conversation 'gdm-password' with active job
Dec 01 11:05:46 morley systemd[1]: gdm.service: Succeeded.
Dec 01 11:05:46 morley systemd[1]: Stopped GNOME Display Manager.

$ grep ^Automatic /etc/gdm3/daemon.conf
AutomaticLoginEnable=True
AutomaticLogin=molgenuser

The automatic login should only be for the first start, shouldn’t it? Locking the screen should still be possible?

(Cc: @halfline as GDM developer)