I've got a an issue (some Cast not even showing a place-holder while being in the NFO). While trying to make some sense on how it would happen, I found someone else mentioned problems with the name and person.xml matching.
It happens mostly with my Anime database as some cast members names are written differently in Romanized form (ex: Saitō vs Saito vs Saitou). I do not know if it could happen with other variations, such as actors with accents in their name but I think it could (I keep my French movies with French Metadata, all others with English ones... didn't notice if an actor playing in both French and English movie are named exactly the same in the Metadata when pulling in different language).
I've had to search for variations on the name and add them to find the one that would appear.
To give an example:
At first it seemed to fix the problem, but then, a refresh on the actor and ZAP!, it disappears from the tv show entry, sometimes reappearing after a Full Refresh on the show. On the actor page itself, sometimes shows appears, but the actor isn't on the show's page.
I ran around in a circle for 2h with the actress above (Chiwa Saitō) because romanization causes multiple variants (I've got four right now, "Chiwa Saitō", "Chiwa Saito", "Chiwa Saitou" and "Saito Chiwa" and I guess it's just a question of time before someone adds "Saitou Chiwa" and "Saitō Chiwa")
If there isn't any way to manage people better I'll simply give up, it's taking me HOURS of fiddling just to get the right cast for only a few shows, and even then they might disappear after a while for no reason or any sequence of events that I can re-create (yeah, just happened to me *AGAIN*... actor is there, then disappeared after a Refresh People... JOY!)
It would be nice to have a plugin like Studio Cleaner for People, so that we could map all those pesky buggers to a single one :/