I’ve only got a few artists with either of those characters, but Plex doesn’t seem to have any trouble with them.
I would double-check the tags, and have a look at this How-To to make sure they are in good shape. When Plex re-wrote the music scanner a couple years ago, it really helped me find errors in my tags. Nearly all the unpredictable results I saw were caused by tag errors.
Feel free to post screenshots of the tags, if you want a second set of eyes on them.
