After several weeks of investigation I received a tip that a technician had rescued the board from the scrap pile and intended to perform experimental work with it.
I am sure there is some clause for which a nonconformance can be written if somebody is falsifying quality data, without the need to accuse anybody of anything. If the data are not accurate, for whatever reason, it is a nonconformance. E.g. if somebody is putting "accepted" stickers on parts that were not inspected or tested, and it can be shown they were not inspected or tested, clause 8.5.2, Identification and traceability, comes to mind: "The organization shall identify the status of outputs with respect to monitoring and measuring requirements..." and the fact this was not done is a finding regardless of whether it was intentional. (Al Rosen cited clause 8.5.2 as well.)