How is this possible?

@Gosho MInkof, this is the popular eth bug and has been part of this game for many years now so it is considered to be normal so to say and anyone can use it. It's not an exclusive feature of this server, it can be found into the original game as well and was left untouched and considered to be part of the game together with some other glitches, the only difference is that it works a bit different here during the bugging process but the result will be the same. Some rumours say that Blizzard hasn't removed the bug, they intend it to stay, and that they need the bugged armors to stay competent when compared to those who do use the bugged armors while others consider the use of any ingame bugs to their advantage to be BM.

BM stands for Bad Manners, like it's ok to use it in PvM against monsters but not in a PvP game.