I agree with you. Hence my use of an e collar. My dog sniffs everything and pee’s/scents on a retrieve. I can stop that behaviour 20m away or when he comes back chastise him. He wouldn’t have a clue what behaviour he is being told off for. A small beep or “flick” from the collar is excellent for this. I have been sure to try the collar on myself to understand what it is that happens. It is not for punishment but control. Which at the end of the day we need to be in.
The old fashioned way for that would be to get out after the dog, walk it back to the spot it misbehaved and give it a row on that spot.
I've seen trainers run hundreds of ms across rough ground to catch there dog and then drag it back to the spot it 1st misbehaved, usually not sitting for a stop whistle.
For the OP if u have done the basics well I wouldn't worry to much possibly just a phase it will grow out off.
But I would go back over basics esp recall on a long line and insist they are 109% spot on.
Wether u use treats, high value treats, praise or retrieves to reward the dog is up to u or a mix of the lot.
Same if u use the stop whistle, reward the dog for stopping quickly by getting a retrieve.
I mind the 1st time I went to a pro trainer 15 odd year ago, nothing major wrong but dog just faffing about on way out/back from retrieves and I was trying to get it up to the next level.
He spent most time going over my basics, I thought my basics were OK, and they were for just a working dog, but ur never going to get a dog behaving at distance if it's only ok close in.
If u persevere with basics and not letting it off the lead where u think it might disobey it might grow out of it.
But the more it does it the bigger ur problem will become.
I can mind on quite a few occasions training with local gundog club when a few of us left dogs in the motor so a few of us could chase down wild labs, really we should of been in a smaller field.
But then dog learns it can't escape