On build 252, I have noticed that the quiet period for my jobs is never
expiring. If I float my mouse over the pending job, it will count down from 5
minutes (I set the value to 300 seconds) and sometimes get into the 3 minute
range, but then it goes back up to 5 minutes and counts down over again.

We are not making any checkins during this time, the SVN repository has not changed.

I just noticed it this afternoon, after upgrading, so something has reverted.
Let me know what I can do to help with diagnosis.