Cable TV Freeze Frame

I wonder if anyone can explain this strange glitch to me. Occasionally, when my cable company is doing what I assume is maintenance and upgrading in the early morning whatever I am viewing will stop, literally. It’s as if I hit pause on the remote except I’m not watching a video. Resetting the cable box by unplugging it fixes the problem. My cable box isn’t a DVR and I don’t have TiVo, so I’d like to know how this glitch happens. Anyone have any ideas?

I can tell you that many DVRs and digital cable boxes will show a frozen frame if you disconnect the cable feed.
In the old days, (and for folks who still have analog cable, like me), loosing the cable means a screen full of “snow”.

a digital tv or cable box or tuner will display the last good frame it has until it is replaced by a new frame.