I wish I had some magic pill, the kind that fixes everything. No, I would rather have the pill that never lets anything break, especially in my training. Do you find yourself having a nice retrieve behavior and now you seem to have mouthing attached to it? Or did you have a killer Drop On Recall, then showed last weekend and now your dog won’t do anything but drop all the time? Welcome to normal dog training! Just normal, tell yourself that as you train, it is completely normal to have behaviors change as you train, the trick is to get them back on track before you have a big problem.
Welcome to Normal!