I feel you on that. I also have random issues with stuff just not show up. Seems to happen with shows especially if it doesn’t like some seasons that have names that change the title of the show. Sometimes part of each season might show up marked as being in correct seasons, but missing chunks of episodes in each season. Also have it happen with movie series that I want to keep together in a folder for the series (but not be an issue for other stuff using similar series folder).

I don’t see it happen as often as I used to, but does still happen. Can sometimes force things by adding the specific movie/show season to the library as a source location.