User blog comment:Willbachbakal/(CB1) Hannibal, the Dread Vanguard/@comment-533780-20150326154812/@comment-533780-20150326170621

Oh right, I think it's because it says his armour 'absorbs all incoming damage'. It makes the 3 seconds seem an awful lot like a cooldown because after the shield is spent, 3s later it would reset, absorbing the next load of 40%-maxHP damage again - effectively giving him a 3s window to take actual damage in between his armour absorbing it all.

If the damage is simply charging him up, rather than being absorbed, it makes more sense and is definitely more fair, but makes all the references to armour and damage-absorption a bit confusing.