Can confirm, soon as I got the armor I started moving amazingly slow. This should be a pretty important fix if you're going to push players to pick up the armor, it really makes the game unplayable.
It seems like mental strength/curse movespeed, it's possible that the quest/armor is accidentally applying it to players with no visible effect.
Buffing with bless/agi doesnt remove the effect, you move slightly faster but it's still slower than normal move speed. Also Panacea/Holy Water dont remove it, maybe getting cursed then cleared may do it, but I dont think I have anything right now to curse myself.