Boss Battles Thread

I was wondering the same thing. Since it's on 2x exp, we are both getting 102m exp - half of what Cygnus gives.
The EXP seems to be divided based on how much of her original HP (2.1b) you do. The heals don't count towards the split, and since we are both doing well over 1.05b dmg each, it just splits the exp half and half.

Or at least that's what makes the most sense to me.

That makes sense. It explains why I got most of the experience from Dyle on a mule, when Dyle kept healing and I eventually killed it on my main.