In my opinion mate, and it's just an opinion
I've found over the years that excitement causes this, put some game in front of the dog and get her working plenty if you can.
Once they get the idea that retrieving leads to more catches they normally settle down and even with a lack of training will still drop em at your feet and be looking for the next run.
Worse case just ignore her she'll come when your walking away from her.
Obviously breed type and bonding, fitness etc all plays a part.
Just how things have panned out over the years for me and the few I've hunted with.
All the best.