FYI - I corrected the server's time since it was running a couple minutes ahead. I accidently set the month to Sept though on first attempt and therefore everybodys read thread status has been erased. Once you read a thread, it'll save again.
Note - this is also why the last 5 minutes of posts are out of order of what you might have expected them. Everything will appear normal going forward as we're past the point in time of the previous server time.