What version of the game you are experiencing the issue with:
Live/Retail

Describe the bug
v418-alpha bricks anything that uses CUSTOM_CLASS_COLORS. Don't create the global yourself, it has a metatable that lets addons register for updates. And DEFINITELY don't add it as a SavedVar for your addon.

https://github.com/phanx-wow/ClassColors/wiki

Thank you for the info.

This was something that was included in the alpha release by mistake, because I seemingly used the wrong branch as a base for the Dragonflight updates. I'll clean it up as soon as I am able