I get this from time to time too. It is a mechanical error of turning rather than tilting my head at anchor. I have finally discovered why this happens and have corrected it after the loss of some skin on my nose.
You might be turning your head to get to your anchor. Try tilting your head to the same angle as you cant your bow. Tilting, rather than turning, gets your eye directly over the arrow and will get you to your anchor without your nose in the way.
Tilt, don't turn.
I hope this helps.
Joe