This issue has been going on for as long as I can remember. I only recently thought to get a recording of it to report here. Basically, when I delete some unwatched shows they delete right away. But if I watch a show for a bit and then decide to delete it, the show re-appears immediately, and I have to delete it again.
I hope this makes sense. If not, here's a video.
I submitted diagnostics too just now. Hope this helps.