The 4pc Akkhan reads: “Attacks from Phalanx Avatars reduce the cooldown of Akarat’s Champion by 0.5s”
Expected functionality: Direct damage attacks from Phalanx Avatars (any rune) or Avatars spawned by other means will reduce the cooldown of Akarat’s Champion by 0.5s.
Questionable expected functionality: This effect would be once per attack
Actual functionality: Individual direct damage instances and individual dot ticks from nearly all sources reduce the cooldown of Akarat’s Champion, and reductions occur PER MOB, not per attack
Extra detail:
Dot ticks appear to trigger the cooldown reduction no matter how quickly damage instances from the skill are registered. For example, Steed Charge-Nightmare performs 20-30 procs on its own on a single mob over two seconds (too difficult for me to count).
Individual damage instances from a single attack, such as Bombardment, will proc the 4pc for every damage instance and for every mob they hit.
All follower attacks, including individual dot ticks from Enchantress Erosion skill proc the 4pc for every mob they hit.
Many of the attacks from the Archangels from the Sanctified Power proc the 4pc.
The only Crusader attack that did not appear to proc the 4pc was Consecration-Shattered Ground, though Consecration-Bed of Nails did proc the 4pc.