The login keyring did not get unlocked when you logged into your computer
I use Evolution to access remote calendars in a QubesOS AppVM, and Evolution stores passwords in the gnome keyring. I had that damned keyring password prompt turned off, and it came back somehow, all by itself. I find it hard to like Gnome and it's spawn.
The way I turned it off THIS time is with Seahorse:
Just find the "Login" button somewhere in the seahorse UI, then "change password". You will need to enter your Qubes login password, which somehow made it into the AppVM. Then at the new password prompt just leave the two fields blank.
Solved for another year?