Heres the setup for the bug:
Holy aura node where every 8 melee hits enemy causes a fire explosion
Shield throw and manifest armor so that when your shield hits your armor, it causes a whirlwind melee attack.
The bug happens when these manifest armor melee hits count towards the proc for holy auras explosion. They DO count but it seems to be off. Instead of taking 8 whirlwind hits to proc, it always takes a weird number like somewhere between 9 and 12, usually 11 though in my experience.
I find the higher throwing attack speed you have, the more the count messes up.