It looks buggier full speed, slow motion it almost looks natural; but if you notice a few times when you're in 3rd person it triggers the most noticeably and the elbow moves down sharply, then pops back into place. And one time the wiggle is very strong.
The scientific brief case key looks like the one that agitates the animation the most; it also makes the elbow move up, where as the handcuff key animation the elbow moves down.
The scientific brief case key makes the arm wiggle more as well.