Many times the dog will get slight wind of a bird but not be quite sure of its location usually caused by a wind shift. They’ll establish point but then start looking around and or start wagging their tail (this is called flagging).
Here are a couple clips of Gunner and Sassy. In these videos both dogs stop at first scent but are uncertain. They both break point, but not to pounce on the bird. They break point because they’re doubting themselves. You can tell by the way they put their heads down and move in another direction that they’re not trying to move in on the bird. I treat this the same as creeping, as soon as they move I launch the bird.