I have a weird bug on my KDE Neon 5.19.4 (based on Ubuntu 20.04) install. When I hover my mouse over clementine's tray icon while it's playing music, it shows HTML text instead of displaying what it should, which would be the visual form of what's coded in that HTML (info like song name, artist name, etc.). Clementine isn't the only application with such behaviour though; even qBittorrent's tray icon shows HTML on hovering over it. Perhaps I'll find more apps with this annoyance as I install them. Interestingly, even Linux Mint 20 Cinnamon has this bug.

Is there any fix for this? I've attached some screenshots to let you form a better idea of the matter.

https://imgur.com/00YOG5e

https://imgur.com/VIKNvaV

I had the same with QMMP so I'd also be interested to know what's going on...
However with my player, I found that I was able to resolve this behaviour by editing that notification script (that the app provided)