happens plenty in MTB land, you take a hard landing, the rim might have a flat spot but secretly the hub starts tearing itself apart, and they typically go in a 'just riding down the street' kind of way (this also happens with cars, they don't blow up at the track, but whilst your slowly easing it down to a set of traffic lights cam belt snaps and engine totaled).
bad hub.
happens plenty in MTB land, you take a hard landing, the rim might have a flat spot but secretly the hub starts tearing itself apart, and they typically go in a 'just riding down the street' kind of way (this also happens with cars, they don't blow up at the track, but whilst your slowly easing it down to a set of traffic lights cam belt snaps and engine totaled).