I have a bitch the same way and I would breed her because I know the dogs in her line (because I bred her and own several of her dogs on her ped) and they do not throw shy does. I think it is more personality than genetic. She is not aggressive but would rather not interact with the general public. She will just ignore them and and stay focused on me.
Now the problem is when (like said in an earlier post) people do not understand the difference between a genetic problem and a socialization problem. Yes Genetically you can pass on bad temperaments. Princesstrish made the statement that gets this breed in trouble. YOU CAN pass this on to offspring that is why you see dogs in the news. People breed crappy dogs and make more crappy dogs.
Back to the OP yes from what you describe I would breed the dog. This is what I would do. Breed the dog and evaluate the litter when they are 12 weeks. Any weird temperaments and I would cull the litter and spay the bitch. IMO