Broadheads DON"T NEED TO BE LINED UP WITH VANES!! and look, he is shooting the 4 blade muzzy, is he shooting arrows fletched with 4 vanes, IT DOESN'T matter if he is.
Sounds like ya might have a little bit of a form issue. If you're not gripping the bow exactly the same at every shot, or are you flinching(grabbing your bow)at the shot, and have you done a spin test with each and every arrow, with the broadheads installed? Could be a braodhead alignment issue!!