0xChat works for this. Just un-mute something, give it a minute to hit the relays, then mute it or something else again. That should fix it. Clearing your Amethyst cache occasionally seems to keep things smooth, also.
Discussion
I uninstalled amethyst and reinstalled (I noticed the update said it will fix mute lists) however I also added Whit to the mute words but when someone commented with that under this note by tagging whit (which is super weird) and it still shows up.
So that tag and the word are two different things. The tag is actually a link to the npub, not text that says "whit" even though it does say "whit" to a human.