No, I think you're right about it being before you put beta 4 on, I misread the date. And I was looking too far up in the file anyway. The version should always match what's in Help -> About. Unless def-use-timer was set to 0 (very unlikely), the timer should be restarted the next time you start SlickEdit, so I don't think a stack from a previous editing session could have done that.
I would have expected a stack logged for something anything that could kill a timer. It could be I'm wrong about it being a timer, or just a bug that doesn't crash, but something else made the timer not get rescheduled. Not as easy as I thought, I need to look a little closer at the code that drives those two features.