Retrieving problems with my Lab

Hey guys-
I have a 2 year old yellow lab (Cooper). He a great dog, minds great, loves the water obviously and retrieved really well until this spring. I don't know what happened but all of a sudden he'll swim out and grab the dummy, bring it in to about 2-3 feet away from shore and drop it. I can't get him to bring it all the way back to me. He'll put it in my hand on dry land but not from the water. I can't even get him to go back and pick it up after he dropped it in the water by shore. It's really weird.  Hopefully one of you guys can fill me in on how to correct this.

Good luck, be safe and shoot straight

dodgeman_29