Oh sorry Skaa. I was still typing my post when yours must have gotten posted. Well, if you like, I'll leave the advice up to the professional trainer since you are responding to this thread which was started by the professional trainer.
However, if you'd like ideas from the rest of us, hang in there. I'm sure someone will have more ideas too. I'll throw in my idea too.
It sounds to me that your dog needs to be controlled when around puppies. That could be dangerous if she bites a small dog too hard....really serious.
It could be a prey response instead of the more typical tolerance of puppies from older dogs. I couldn't really say. But some kind of counter conditioning probably needs to take place where your dog sees a puppy from a distance and while she's calm and in control, but is also seeing the pup, she is given special treats and praised. Gradually you move closer. You can get someone to help you. They hold the pup on a leash and you hold your dog on a leash (make sure it's secure) and stand 50 ft or so away from eachother. Walk laterally (side to side) with your dog while that dog stays in place. As long as your dog is staying calm, give treats/praise. Move just a little closer and keep walking back and forth, side to side, not toward the pup. If your dog becomes agitated and reactive, you've gone too close too soon. Be careful not to reward if your dog gets reactive. This will take some practice and someone willing to help you.
Also try teaching your dog to pay attention to you on command. "Watch me." Take a treat and hold it in front of her nose and then bring it up to your face. As she follows with her eyes and looks at your face, give her the treat. Do this several times. Then, start saying her name and if she looks at you, say, "watch" or "watch me" and give her the treat quickly. Do it every day several times, but for just a few minutes. It can get boring. Do it in different locations and contexts. When she starts getting pretty good at it, try when she's not paying attention, but in a low distraction area.
Around the puppies, if you get nervous, tense, excitable or punishing, all these kinds of emotions can influence your dog highly. She will see that her leader is upset and will become more uneasy. You want to portray a very in control owner who is calm and not one bit concerned about the other dog....like it's not a big problem at all. Act very confident. Dogs really sense our moods. And associate the puppy with good things....treats, fun, happy voice etc. But if she's lunging or snarling, don't reward or try to calm her. Soothing her and talking to her will be like a reward for that unwanted behavior. Just give treats and talk when she's being calm.
Anyhow...this may not be a cure-all and you may need some better, "hands on" help. These things aren't always easy or quick.
Maybe someone else will come along and give you some ideas. But I caution you against using punishment tactics or stern corrections, as these are known to often agitate a dog even more and make them associate the thing they're reacting to (the puppies) with aversives or fear. If the dog fears being punished everytime a puppy is around, he's going to have a mal-adjusted outlook on puppies. You want to make him "like" puppies.
