My lab has done excellent in rally and all of a sudden has decided to start jumping out of the ring after the first jump in the excellent class. Any suggestions on how to stop this?
More training and proofing.
You may also want to make sure that you are talking enough to him so that as soon as he's in mid-air over the jump, he's being told to HERE, HEEL, Get Back, what ever you use to keep him at your side.
I found that if I wasn't verbal enough with Grace approaching a jump, she'd try to heel around with me. But when talking to her about the jump RIGHT out of the last exercise, she's excited enough to go over and lots of talking gets her back.