"If a trial or test problem does develop, your best bet is to quit running competitions altogether for quite some period. You'll want to completely eliminate the problem and have new ingrained habits before you run your dog at a trial of hunt test." The Retriever Journal.....Mike Lardy"
The bold section is the most difficult part to come to grips with. It is almost never a two week fix. Several months might be enough (with the emphasis on might).
Defining the "quite some period" is difficult because duplicating the issue, de-programming and creating new expectations in training often requires unrelenting patience.