Awesome..Way to go Pappy. Teaching him right. Congrats to your grandson.

Semi - I've found that differences in cheek pressure on the stock, where the rifle is placed on the bags, how tight the rifle is held and any other inconsistency in shooting will change the POI. When I'm shooting off the rest I try to be conscious of every aspect of points of contact hoping to eliminate as much human error as possible.
As for the two targets with the first shot out of the group, it could possibly be the scope's springs are 'sticky' and settle in after the recoil from the first shot after adjustment.