I think you are right re: the protector not being fitted (especially if the ball is hitting it on launch), I just thought that if the metal protector fits over both the inside and outer part of the PF edge (not sure if this is the case; looking at it again, prob just the inside), then the outside part might've been rubbing against the inside of the cab, but as you say, likely not the case.The protector wouldn’t stop the playfield sitting in the right position?
The balls is hitting the protector - it probably hasn’t been installed properly.