Most vets won't tell owners the truth on weight. I've seen a vet tell a man that his dog looked great...the poor little dachshund was so fat his "manhood" drug the ground!
I had one puppy that I sold that was like that...I want to say that he said he was 45 lbs at 4 months and warned him then that it sounded like he was getting too big too fast and 80 lbs @ 6 months old...dam is 65 lbs, sire was 75 in working condition. That puppy was dx with OCD in his shoulders not too long after 6 months if I remember correctly...OFA says it's genetic, other studies say conditional from overfeeding. I think it's the same as HD, there's a genetic factor and a conditional factor (otherwise we wouldn't say keep them light, no excessive jumping, when they're young, etc). That is the only puppy out of 4 large litters that the female had that was reported to have that problem, there was one more that was a bit heavy when I saw her at just over a year old and the owner thought she was solid muscle...I gently told him that she should loose a few pounds.
Which puppy is sitting on the GSD?