Unfortunately, I'm in the same boat as you. Trace used to come immediately when he was outside, now he's decided he doesn't have to
When we go outside at work, he's now on a harness. I just don't see any other way around it. We are on a busy, busy street and cars cut through our parking lot. I'm gonna get some treats and try those at home. Perhaps he'll learn coming to mommy is a good thing. I did train my golden the parameter's of our yard by walking her along the property line on a lease and pulling her back w/ scolding her if she went past. It worked, but I think Trace is too tiny to try that