Ok ... with the help of DEBUG logs, it's working as you expected, though not quite how I would like
The first login does work.
Then after deleting and re-adding the account the logs show:
Refresh user membership: No refresh. Interval time has not elapsed.
Can a users interval time please be reset to zero after each account creation has been detected?
As a workaround for now, we'll see how lowering membershipRefreshIntervalHours goes.
Thanks heaps