Enemy player movement very jagged/robotic, especially when looking at them from distance through scope

[VancouverCanada 0]

Almost impossible to hit. It's hard to tell if it is lag or a drop in FPS - almost looks like a combination of both, but it makes a player almost impossible to hit - especially with the amount of annoying scope sway.. Like impossible. It's like my character has drank a two six of vodka chased with a couple bottles of cough medicine.