I use Ubuntu 18.04 with Gnome Shell and gdm3.
When I press Ctrl + Alt + F1 I see gdm3 home screen. My current desktop session is on the second "screen" Ctrl + Alt + F2.
Is it a bug?
I had a random bug and I don't know if it's related to the duplicate gdm3 instances: when I logged back after locking my screen, I was unable to reopen with session and I had to reboot the computer by pressing Ctrl + Alt + Del on another screen, like Ctrl + Alt + F3.
I removed gdm3 with sudo apt remove --purge gdm3 and reinstalled it and there are still 2 instances.
Update: once my screen is locked, sometimes I can't log in again as my password is rejected, but if I switch to the first "screen" with Ctrl + Alt + F1 I can log in again.
