It happens on all servers, even on DTV. Blocks not registering, Swings going clean through people, swing animations not showing up, getting hit by swings that missed you by one m, first getting hit then seeing the animation, hitboxes floating 1m in front or behind enemies for ranged, walking through each other, rubberbanding and teleporting, projectiles flying through people a lot. As far as I remember it all started with the last patch to this extend.
Cmp said something about clients and servers not being synchronized, I dont know whether he was referring to a general issue that has always been there or if he was referring to something that happened with the last patch. Its making the game kinda unplayable some times.