So cranky, maybe a pain in the ass, but still deliver the bacon?

Could be the credentials themselves get you marked for promotion.

Monsieur Bouvier was a high school French teacher who was one time the only teacher with a PhD in my school district. He knew a lot about pedagogy and evaluation and certainly French but being in his classroom I think he lacked "soft skills" and was not good at dealing with bullshit which is a lot of what the teacher job entails.

He got promoted to assistant principal on the basis of his credentials and put in charge of gifted and talented programs, I think the honors program succeeded precisely because people above him bypassed his authority and overruled him quite often. He was not really a good leader or manager -- as assistant principal he got to do some of what he was good at but he had to do more of dealing with the bullshit that the first and second tier couldn't deal with.

My school had Roy Downton as principal for the longest time and he was really great at the job and hard to replace. There was a lot of jockeying for the position and Bouvier lost out and Mr. Adamankos finally won. I think Boivier's credentials got him a certain advantage in promotion but fortunely he didn't get promoted too far beyond his competence.

im considering the possibility that the performance reviewer is harder on the overqualified candidate for any subjective assessment because expectations are greater or the goal of the lukewarm assessment is to motivate or challenge more capable candidates. an underqualified candidate only has to keep up to pass subjective assessment and the motivation is built-in

many people are immune to basic motivation tactics but im surprised how many of my peers i see influenced by reviews which seem mostly motivational, and occasionally political, to me