Shows like this one can be a bit tricky due to some online sources deciding to use 1 show with 2 seasons compared to 2 show enteries.
Pro tip is to add a matching id in the folder name for the show so plex can precisely match against what you want. So, basically rename the top level show folders to this …
The Haunting of Bly Manor (2020) {tmdb-109958}
The Haunting of Hill House (2018) {tmdb-72844}
Plex will then match off its id from their metadata cache database and pull the correct data.
You can also just split appear and fix match based off the ids which is fine but I typically find it better to name the folder with the ids so its stored forever.
BTW… you might also need to plex dance the two shows if you still have problems after the rename.
