Yes, CMU was fined because they were breaking the same rule, albeit in a different way, that Michigan was.
Re; quarterback coach Kostner: "The NCAA's investigation found that bringing Stalions in to decipher the Spartans' signals in real time was the brain child of former quarterbacks coach Jake Kostner. Kostner reached out to Stalions, then engaged two staffers to get Stalions CMU coaching gear and a sideline pass, where he stood "in close proximity" to CMU football staff."
As for two other individuals: "the NCAA found Mason and McGee initially provided "false or misleading" information to enforcement staff before turning an about-face and before providing "critical information" to the investigation."
As for CMU itself: "The NCAA found that CMU "demonstrated exemplary cooperation" throughout the investigation and actively assisted the NCAA in its collection of facts and records."
They got punished for breaking the rules and they all should have.