I have three very large dogs. Two gsd's and one rottie. I know their personalities quite well and would never leave a baby unattended with none of them.
My rottie is very protective of childeren and babys, so he may take the baby and hide it from me.
My female gsd hates loud squelly noises. If baby was squeeling to loud, she may want to shut it up.
And my 10 year old gsd has a high prey drive. He once killed and ate my 2 month old kitten. It was so sad. I couldn't get him to drop the kitten.
So, they knew the dogs personality and did nothing to protect the baby. Children smell and are totally diferent than an infant. They should have properly introduced them. I feel bad for both dog and baby.