Sounds like a bit of a weird one but have you ever noticed that your dog often behaves the same way in a certain environment?
It can be a good or not so good behaviour and I'm not just talking at on the same walk but it could be a section of that one walk, or someone's house or that one bit of open grass or when we go through that gate?
It can sometimes take us a while to notice “oh you've done that again in the same place as last time”
There is a couple of dogs I walk that I can guarantee will start playing at certain point on a walk.
There is a certain dog that I can guarantee, if off lead will nick off at a certain points on a walk.
There is a dog that will get uncomfortable at a certain point on that walk.
You may find that dog is reactive on one walk but fine somewhere else. Or may find your dogs recall is terrible in one place but fine somewhere else even with the same level of distractions.
Kira my dog used to revert to a puppy in one friends house after that was the first house she visited when I got her.
Our terrified of the world Ridgeback Shumba in process of his training was a lot more receptive and chilled on one walk but unsettled on others.
Dogs are creatures of habit and their memories for good and bad are better than we think. Awareness of our dogs behaviour in certain areas helps are chances of changing the association it has for them.
So the dogs that played in a certain area on a walk got to the point where they were over high and harder to control in that area. I bypassed that walk for a good month then when I did go back I engaged them in a task just before the silliness kicked off and changed the association of that area over time.
The dog that nicked off got put on a lead before we hit those points, such a simple but often over looked option.
The dog that was uncomfortable at the certain point on a walk I could of slightly changed my route but what a actually did was to create a feed point and play to change where his head was. I'm not sure what happen at that point. He could of tripped strained a muscle there or got poked by a stick, as he's sensitive like that. All I knew was I had to change the way he felt at about that spot.
As for reactive dogs I have worked with a few that are very reactive when walked from home but when walked away from possible home “territory” are a lot easier to control and more relaxed. Probably as home territory had repeated bad confrontations or regularly see the other dog that doesn't like them either. Areas of particular upset are trigger points but this can change to a area where hotdogs rain from the sky hence changing association.
As for our beloved Shumba who could easily freak out and not recall out of past related fear. One week of walking in the area he enjoyed followed by the odd change built up a bank good associations to walks and trust building.
So basically if your dog shows an environmental behaviour that is good embrace it and enjoy it as long as they don't get so happy they can't hear you any more.
As for behaviours you'd rather they didn't happen even if it is they always pull at this bit of the walk, then you need to change your reaction to it. Avoid for a bit if possible if not change the habit of what happens there to a behaviour you would prefer. Sit, hand touch, sniffing game, wait, a game with you but some thing they generally like engaging in. Then do it like a new habit, changing the thought process and association they have with that area and with any luck problem solved. :)