Could easily lose focus on the nitty gritty of product ownership (user story building and details)
He consistently brought up the fact that he slowly became disengaged and discouraged in his previous jobs because of the approach
Slightly highfalutin explanation of what he perceives as the Product Owner role. There is a feeling that he is using the PO role to "get his foot in the door" (for a future role) rather than being genuinely interested in having a real "go" at being a PO and making that work well.