"Starting class does not meet multiclass prerequisites - Prohibited by: Warlock"

This bug seems to have occurred within the last few weeks, as I've theorycrafted this character a bunch without issue. Can someone make sense of this?

https://www.dndbeyond.com/characters/173401733/p5A7v4

Charisma is plenty high to multiclass out. 

I don't know why it doesn't work, but it's also not woking on one of my characters who is already multiclassed (I couldn't add a third class). Same error:

"Starting class does not meet mulitclass prerequisites – Prohibited by Warlock"

Just for fun, I checked a non-Warlock and got a similar error for a Rogue. Looks like multiclassing is borked at the moment.

The same thing happens with Paladin. It's very likely something to do with the new World of Warcraft classes that were recently added.

It’s worth noting you can remove the multiclass restrictions in the character creator settings.