Somehow Sosiel reached level 20

For context, I’m playing a Paladin on the Angel mythic path, currently level 11, angel level 2. Sosiel somehow got enough experience to level up to max level and I have no idea what is causing this. While I’m flattered that he completes his training ahead of schedule, it is really not normal for a character to reach this point when in act 3. Anyone else come across this?

Yea that’s the infinite level up bug… happens quite often, possibly with all characters. The game will simply not stop you from leveling up