I have been seeing this issue for a little while but decided to post about it today.
I notice that when searching for movies (see screenshot) I often get a lot of movies that the images never generate or generate very slowly. This doesn't only occur when I do a search. It often occurs just browsing the library via the web gui. It also will do it when I am trying to change a movie poster and it is searching the web. I often can get the images to finally fully populate if I refresh the browser or exit and retry the search.
I never see this issue when browsing via any app such as on the Apple TV or on my iPhone.
This is happening on both Chrome browser and Edge. My DVR version is 2022.10.01.1300.