Same issue, have three accounts, the first two (gmail, o365) works fine, but the third one, a gmail account, doesn’t appear in the list. Reopening doesn’t help, re-auth the connection doesn’t either.
I clicked the window option in the top bar, select the third account only view, works fine. Switched back to the main screen, and all three accounts showed up.
Maybe some kind of bug in updating the list? And can be fixed by manually updating it?
Endeavour OS x86_94 5.15.12-arch1-1
1.9.2 6e14dad1