Eric, sorry for the misunderstanding. There are others that I am sure will will jump in with more experience than I, but I will give you my thoughts.
One cornerstone of FF is that its a step that transitions from asking the dog to demanding compliance while establishing you as the alpha. With this step being done by a pro, you will need to follow through with opportunities to establish yourself as the master and expect 100 % compliance with every command you give the dog.
I'm not sure what your ultimate objective is with your dog or to what level you plan to take the dog to? Next steps in training with some programs is now pile work and lining. The fetch command is used in some of these drills then transitioned to the "back" command.
The bottom line is if you command the dog to fetch he must fetch and hold the object until you give the command to drop / release. On marks, he retrieves and holds the bird / bumper until commanded to drop. Your pro should show you what process he used to enforce the command fetch / hold (maybe ear pinch?) so you can be consistent in its enforcement when you get the dog back. One area that I think seems a challenge for many dogs is in making a water retrieve, many dogs want to drop the bird and shake when exiting. Don't let him, make him heel and hold till you command to drop.
I'm sure your pro will give you some direction and thoughts about compliance and challenges with your dog since he's had him for few months