Version 4.59.2
I dislike the chosen posters from time to time, and today I went to use the plex gui to change it. I was able to see the options, and click on one. But once I click on it, all I get is a black rectangle for the movie/poster instead of what I chose. I am able to go back to the one selected automatically, and that will display.
I had this happen many years ago too, and a version fix eventually fixed it.
Is this a current issue by chance?