It is not normal. The puppy is just a baby. I've got a 16 week old puppy right now and there is absolutely no reason to put that on a puppy that age. I do use one with my 5 year old, so it's not like I'm against them. They work well IF used correctly. It's not being correctly used right now.
You need to show your puppy the right way to do something before you can start correcting the wrong behavior. Positive only at this age. Clicker training works well. Their brains are like sponges now and they pick up things very quickly.
I can't believe a respected trainer or trainers would think it's ok to put a prong on a puppy this young. Mind boggling almost.