Same thing used to happen on Halo 4. Used to watch bullshit like this all the time in theatre mode. Too many times I'd strafe out of someone's fire only to see the bullets curve towards me and not continue in a straight line. In theatre mode you'd seen the tracer fire at a slight angle when leaving the gun barrel. I suppose most games are guilty for it to a certain extent but it's beginning to put me off shooters knowing that a total retard can go toe to toe with me even when he can't shoot properly.