I was in pvp on the boat map when this guy was heading towards me so I splashed him with a weakness potion. I had full iron Armour on and so did he. He killed me in 2 hits even though i healed a bit after the first time he hit me. He claims he had strength on but there were no potion effects on him until I splashed him with weakness. Strength + weakness + diamond sword does not = 16 health damage on iron armour. I have put the recording of this whole thing where he killed me.
See for yourselves.