Blizzard(apocalypse) bug

Sorry I don’t speak eng well.
I used Google Translate.

Blizzard(apocalypse) -> focus and restraint set(When you hit with a resource-spending attack. deal 50% increased damage for 5 seconds.) hardly applicable.

Almost applies when there are multiple enemies.
It does not apply very much when it is a prime number.(Especially the Rift Protector)