[CLIENT] Masteries won't save/activate if named "Aatrox" case-insensitive

It says: "Error An unexpected error has occurred"

I tried "Jax" and "Ahri" and they work fine so I think it's just "Aatrox" "Aatrox " or "Aatrox"+someOtherCharacter works though, so just "Aatrox" or "AATrox" or "AaTrox" etc don't work.