Long bird behind momma-poppa, out or not, go bird off to side. Momma retires into poppa. Pick up go bird, Then poppa. Now what?
Most, and I would never say always, but most times you are going to work pretty hard to pull out that momma bird, and try not to let them get the long gun.
Because it is so tight, many dogs will lose memory, and think they have picked up that bird, if they go long first. So, in that case, you might really want to get the bird you want, not the one the dog wants.
Do think it can be which dog, some are ok going back where they have just been, others not. But, maybe that is function of not so great training, although we have had both types, trained essentially the same.