A narration is widely repeated in the community. A student classifies it as the technical category of mashhur report merely because of that popularity. The error is substituting everyday renown for a defined category of transmission.
The book distinguishes mutawatir, mashhur, and khabar al-wahid. Their classifications depend on how a report has been transmitted, not just how familiar it sounds. A second claim—“Its message seems correct, so its chain must be certain”—also requires independent evidence.