Edit: Just noticed that you did test it out XD
Yeah, it's kinda weird how it doesn't work, but I can kinda see the benefit.
It's more like "these are the main tags that will be used overall". And if you're using the same tags for each episode, it's kinda redundant, you know? It's already been covered by the main tags in the comic.
I can only suggest including all of the tags you'd want to use as the main tags or something.
Though, I do wish the tags weren't as specific as they were. Like, it can help to clear out the search tag and be the only one there, then again, I dunno if a reader will think to write the tag perfectly each time.