Apparently it isn’t just when a movie is playing. I was trying to get a movie to play, but kept getting an error message (claims it lost connection to the server;more on that below) and now it is giving me that white box with info from that movie while I am in the screen showing my movie library.
As for the error message, it is saying Playback has stopped because the connection to the Plex Media Server has been lost. I know this is a separate issue, but the other threads I’ve found mentioning this haven’t had any comments by Plex employees and no fixes listed (links below), so I figured since I had your attention, I should mention it. It only affects certain videos, while other videos work fine. It also only affects my android app (newest version from the Google Play store, downloaded 2 days ago), but running it from my Windows machine will play those videos with no problem.