Took a look at TC this morning to find Almost all my builds with "?". Looked at the database and saw that most of the tables were mostly empty. My guess is that the purge process got a little ambitious and got rid of most all my builds.
This was a fresh install and most of the builds were from yesterday, so I don't think that the builds should have been purged.
When I look at the Purge policy, it looks like there are no rules (I started this build with a fresh database). This has not happened previously, so I'm guessing that some default rule which existed in previous builds didn't make it into this one and so cleanup made things very clean.