Personal Damage Bonus - Nerf or Bug

Try raiding with a smaller group if you want a bigger personal damage bonus.

Here is what I heard: 5-15%: 1 ball, 15-20%: 2 balls, over 20%: 3 balls. It is really difficult to get 2 damage balls in a group of 10 if no one rejoins and the counters used by the players are roughly the same. I guess you are right below the 15% threshold this time