My dog runs to where the leash runner will put his leash as soon as on the course and is headed in a direction  where he sees it.  This may be only after 5 or 6 obsticles.  Most of the time he takes the last jump with the automatic timers and thus ends his run.  We have tried things at practice and in class, but HE ONLY DOES THIS AT TRIALS.  Is there anything I can do in the ring to stop this behavior?  He is a very fast dog and was doing very well in agility until he started doing this.  so far it has cost us 6 Q's.