OK - I know numerous topics have been posted about weird things happening with tumbnails, but I haven't seen one describing a situation exactly as I am seeing.
I am currently running 11.1.98, but this problem has been around for as long as I've been using the thumbnail feature. The view I'm looking at is "Audio>Artists". When I first start Media Center, all of the thumbnails are visible. However, when an Artist has more than one album, Media Center will sometimes cycle through all of the album thumbnails for that Artist and sometimes display a static thumbnail of the first album.
I don't notice a pattern in terms of which Artists will cycle through album thumbnails and which will not.
That is a minor issue compared to the problems I am having with disappearing thumbnails. At startup, Media Center will show all thumbnails, but after a few browses into the folders, some of the thumbnails disappear. I can restart Media Center and all of the thumbnails will be back, but the issue soon re-occurs. Curiously, the same thumbnails seem to disappear each time. By disappear, I mean Media Center displays an empty square. If I continue to use Media Center for several days, I notice that I can no longer regenerate the thumbnails my simply restarting Media Center. Instead I have to delete the "thumbnails" folder and then "build missing thumbnails" from the "Options" menu. Any suggestions?