I'm going to try this question here as it's a "performance" issue so even if you don't know flyball you may understand and have suggestions.
Rocky and I have been learning flyball for very close to a year now. The goal is to teach them to jump over four small hurdles, turn on the box (think swimmers turn) and grab the ball as they turn, and run back.
We are still on the box turn (swimmers turn). We have the actual TURN down pat. We've added the ball more recently. On our first "practice at the box" he'll do great. We start with just a turn then put the ball in and unless he fumbles it, he brings it back no problem (while doing the turn). But after a good 20 min break, when we practice again, it's like he's forgotten everything. he either won't do the turn or won't get the ball (mostly won't get the ball).
Is his attention span just that short? Or is there something else going on? this happened three weeks in a row (one practice a week). why does he go from a great sucess to total memory lapse?
I'm not familar with fly ball. What does your instructor say?
FWIW, I think it's pretty normal, particularly in the early learning phase for the dog to seemingly "forget". I don't think they are really forgetting but probably just trying to more clearly define what is expected. In your case, he turns right and gets the ball the first time and you praise him. The next time he may try turning to the left, running faster or slower, or missing the ball completely just to see if he still gets praise. You know...just defining the requirements.
My other thought is that it could be too much too soon. Any time a dog struggles with a new exercise, the cardinal rule of training is to back up to where they were last successful.
Also, is there a way to separate the ball portion from the rest of the exercise? Sometimes that helps too when you just practice on the problem part separately so the dog doesn't think the rest of the exercise is the issue and start trying to fix things that aren't broken.