Tivo Roamio keeps switching to letterbox for all video

Today, I noticed that my Roamio Plus which was working well until now suddenly started showing video only in letterbox format. This is for live (HD) channels and recorded HD videos. The zoom button has no impact at all.

When I try getting into SD version of settings menu etc., it resets to proper full aspect ration and switches back to letterbox at random. I have seen same video playing in full screen for a minute and the moment I clicked tivo menu, everything goes back to letterbox and...

Tivo Roamio keeps switching to letterbox for all video

Tivo Roamio keeps switching to letterbox for all video