AFAIK(unless this is a new feature I’m not aware of), Plex does not scan/use title tags from MKV files… Though I seen people stating otherwise. I have never seen it myself.
But… If you have indeed removed the TITLE tags then you will have to refresh metadata for the correct info to populate.
TV shows can can a little more tricky cause it could cause Plex not to recognize whole series and/or episodes and could also cause plex to detect(identify) then as another series or the episodes part of another series entirely.
That’s a bit troublesome. The Plex Dance should have worked. This makes me think the TITLE tags are still there or you forgot a step in the dance… Remember, you still got to empty the trash. If not then the items will be “recycled/unavailable” state until one of the following conditions are meet.
- Trash is empty.
- Plex finds the media again.
 If it’s item#2 then Plex will just reuse the previous stored information and remove it out of “recycled” state and flag as available.