Sedation can do weird things to even the sweetest dog. My parents late wheaten terrier had to be basket muzzled and monitored carefully coming out of sedation. He was a sweet, derpy boy who turned completely feral when waking up from dentals or any type of sedation. He punctured at least a tech or two during his lifetime because someone wouldn’t want to be “mean”. In his case, he was painfully dumb and I think his response was a complete fear reaction based on being disoriented.
Conversely, one of my cat’s came to me labeled as unadoptable due to a long history of being a biter. He’s never tried with me and is a total ham at the vet. However, at all times I treat him like a biter. With him everything is an ask not tell, we work on his timeline, and I don’t force an issue. If a vet tried to manhandle him I have zero doubt he would live up to his reputation.