Just an FYI, Fallen Avatar in phase 1 will only take 1 hit of Comet Storm instead of 7. This is just an example from my logs. Comet Storm is being cast by the legendary helm, you can see the first few hits are single hits with no folow ups. When the target is Maiden the Comet Storm ability acts like normal and splashes to Avatar 7 times as you'd expect.
From what I can see in phase two it acts like you'd expect.
https://www.warcraftlogs.com/reports...96&view=events
I reported the bug in game, if people could do the same would help.
Cheers