My bridge boy Sneakers was that way. Even in the yard. We always muzzled him when people were over. We just learned to live with it. He was fine away from the house. On walks people could pet him, meet n greets and at the vets. I mentioned muzzling him at Christmas to one of the vet techs and she was shocked. She said why when he was such a sweet boy.
It was just the way he was, I miss my crazy guard dog.