So I had a similar situation on a 4th down except the A was lined up in a normal formation, not punting. Lined up with hands on knees and at a signal by the Qb the entire line quickly went into a 3pt stance. This was not something they had done at all during the game previously, it drew a defender into the neutral zone. I threw the flag and was going to call false start as I was the Line Judge and only saw the tackle and guard on my side do this. Went to my white hat and he said that the entire line did this so it was ok and we should go with the encroachment on B. Being a first year official I wasn't sure and went along with this.

Was my initial thinking correct on this or what we ended up enforcing?