I've got a 5 year old BLM that I got at a year old from a pro trainer. He was force fetched and collar conditioned when I got him. I take him out about five days a week and throw him marks. He's always delivered to hand and released the bumper on command without issue. In the last couple weeks I've noticed a couple times I've told him to release the bumper and he's held onto it. Obviously I want to correct this right away. Just curious what the proper way is to correct this? I don't want to create any other issues.