1. Log in as user in a browser window
2. Go to a project version and click on a language
3. Log in as admin in a different/incognito browser
4. Go to administration, server monitoring
5. Click Invalidate HTTP Sessions
6. In the user browser, click a different language
The regular "You have been away for too long..." (view expired exception) is displayed, but the log also shows
It appears that this occurs when a transaction is created with an expired session.