For me the main cause of coming out of your spine angle at impact is improper weight shift toward the target through impact. Any flat footed swing with no finish would give the player the coming out of it feel. By loading and then shifting your weight toward the target to finish should help this problem. A couple of great drills would be hitting balls off a slight downhill lie on the target side of the shot or the Gary Player drill of actually stepping over and walking toward the target after the strike. Very important to maintain posture and I think these drills will help! Good luck and strike that finish pose!!