I totally call that hacking! Erza totally was moving to quick, he left something behind! (funny part is that his body was stuck there on my computer the whole fight, love bugs, sometimes they are funny)
Yah got a couple of screenshots like that too, with various armor and body parts staying behind and the rest moving on
lyantha got the same bug with me the other day... and yesterday i saw some1 in raid transparent (i could see helm, gloves, boots and weapons floating)... kind of reminded me of some old guildwars 1 mobs xD