Server Version#: 1.19.1.2645
This seems to only happen in web browsers. I haven’t had any problems on the AndroidTV app or on my phone. It seemingly happens to both custom and default posters assigned to both movies and collections. When I empty out the cache of the browser it works as normal, but after a couple of days 4-5 random posters disappear again. I have tested in both firefox and chrome and both are having this problem.
If I click on one of the movies with missing posters the poster will come back when Im browsing that specific movie and when I click back out to the library the poster will show for a second or two then disappear again.
Here is a video illustrating the problem: https://streamable.com/8x97fh