Visiting a new topic page in mediawiki/metawiki doesn't mark the notification as read most of the time while testwiki/test2wiki work in all my tests.  This turns out to be a database replication delay, fetching new title from slave in the same request is very likely to fail, testwiki/test2wiki covers the issue with a delay in network request to extension1 db.  I couldn't test this in beta labs which is set up with replication delay, it seemed to have some problems.