Comment 4 for bug 1391764

This issue could be due to https://bugs.launchpad.net/mir/+bug/1377968
Essentially, the Online Accounts authentication service is locked in a hidden trust session triggered by a scope. OA has no way of exiting from that error case, because the trust prompt doesn't send that information back apparently.
The problem is more visible because scopes are starting to use OA more intensively, whereas they were not previously.