Sometimes, pausing only pauses for a few seconds before restarting on its own

I've noticed this a few times recently. I'll be watching live tv, I get a phone call (or nature calls, or whatever), I hit the pause button, which stops the action, but then 2,5,10 seconds later, the action restarts without my permission. I don't think my Tivo has that much stuff on it, so there should be space for recording this live tv on the fly (by the way, is there a way to check how much memory is being used as a percentage of the total available?).

In doing my preliminary searching and investigation of this issue, I've seen some people click the RECORD button, then pause, but this seems like an inelegant solution.

Any thoughts on what's going on? Thanks