I had a MacBook Pro 2016, and I had problems with the B key produces
bb about one third of the times I hit the key. After repair and several months later, I had the same problem with the N key.
I now own a MacBook Pro 2017, and I have the same problem with the M key, but maybe with an occurrence of one in forty, which make it much harder to demonstrate.
It's always the same zone on the keyboard, I was wondering if several people had the same problem ?