Signal breaks up: CableCARD or TiVo problem?

So I have a Premiere that dates to 2010. Sometimes, I'll be watching a channel (usually a local broadcast channel), and the signal will start with little glitches, then become completely unwatchable over the course of a few minutes.

Changing the channel and changing back will fix it.

Is more likely to be a sign of a failing TiVo, or a bad CableCARD? In my mind, it could be either.

I have another TV which does not exhibit the same behavior when tuned to the same channel, so the one thing...

Signal breaks up: CableCARD or TiVo problem?

Signal breaks up: CableCARD or TiVo problem?