Yes! ...I'm that sort of inconsistent shooter. Having said that though, I don't think it's the anchor. Something else has wandered... could be a slight tilt of the head, or a slouch of the shoulder or a firmer grip than usual on the pouch etc. Sometimes we may be shooting tired and that affects our form in ways we may not immediately perceive. My usual approach is to resort to instinctive shooting for a bit and it kinda auto-corrects...