When Jeff is speaking to Amy and Isabelle (the conversation where he says "We'll make it a threeway"), his arms jump positions multiple times between shots. Sometimes they are behind his back, sometimes down by his sides, sometimes held out in front of him, or some combination thereof.
When Amy, Dina, and Glenn are confronting Jeff, at one point Glenn pulls out and opens his wallet. He holds the wallet open in front of him with both hands. When the shot changes, he is suddenly holding the wallet closed down by his side in only his right hand. When the shot changes again, the wallet is back open and held out in front of him in both hands.