I am transitioning my guy into the field with blind work and have run into an issue. We have used this particular spot several times and he has the same issue. I begin the session with a review of 3 handed cast and a few whistle sits while walking out to the area I will use for work. The grass in this particular spot is approx. shin high and there is a 2-3% grade up hill over 50 or so yards. I will walk him at heel to the first spot the bumpers are placed and from there walk directly to the second spot where the bumpers are placed and then return to the "line". Line up pup and send to the first location. This is where it gets interesting. He will take off on the correct line however he will stop on his own and hunt larger clumps of tall grass and milk weed type vegetation. I will blow whistle he will sit and I will re direct however he will return to these same giant clumps of grass. I will go out and physically pick him up and re sit him and stand over him until I can direct him to the bumper and return to heel. Ten or more sits and casts. Second blind I line up and send he pins and takes a perfect line. No sits or casts. I'm a bit stumped as to why he hunts the tall vegetation but also glad he doesn't avoid it if that makes sense. Thanks in advance for your input.