18.04.01 adding google online account appears to fail with 2-stage verification

On upgrade to 18.04 (from 16.04) my google storage did not show up in nautilus. Online accounts said authority had expired. Re-entering the password followed through to the verification message on my phone but the account still showed as expired. I found a similar bug in launchpad for 17.04 where one fix I tried was deleting the record in ~/.config/signond/signon.db. I made several attempts signing in to google and deleting/readding it from the online accounts app which always ended after the verification with neither apparent errors nor progress. Trying my wife's ubuntu login I found her google account missing altogether so set her up without any problem in gnome, but she doesn't use 2 stage verification. I logged myself in again but choosing unity this time to find my google account was up and running. Logged in again with gnome and this time my google was fine. The signon db remains empty.

Later, while the entry still showed in nautilus left pane, No content was visible and a message said communication had been lost. Back to online accounts app, log in to google again and the app still showed a warning for google and nautilus had no content, but log out and back in to gnome and all well again. Rechecking the wife's gnome showed her google still connected without problem. Rechecking my signon db still shows no entry but then found wife doesn't even have the signond directory never mind the db file.

2 problems here -
1 - why can't the app complete the job of logging into google without logging out and in to gnome?
2 - why does the authority get lost again?

Another question is why the upgrade should make it expired at all?