When I finished Act 1 and went to Act 2, my companion’s shadow was missing, and it looked as if she was hovering over the ground. Only her bow had a shadow.
I couldn’t test to see if it will fix itself if I close the game and re-open it, as the free beta access expired. I also couldn’t test to see if the Act 2 companion has a shadow, or if the shadow will return if I enter some other zone and then come back.