Filtering TV shows by audio/subtitles is not done recursively anymore as it was before the feature broke and got fixed with #10189 ((Library) Filtering shows by audio or subtitle language would fail).
Example:
If you have english subtitles for a tv show for season 1 and 3, but not 2 the filtering isn’t done recursively and therefore it thinks the entire tv show got english subtitles.
The same goes for audio.
Plex Web Version#: v4.0.1
Server Version#: 1.16.3.1402