The penalty for a restart violation is a pass-through. If there aren’t enough laps to enforce the pass-through, the penalized driver gets posted to the tail of the lap he’s on.
The scenarios for waiving off a restart are very limited - something has to happen before the leader gets to the second line of the box that renders the restart improper, and they throw it right away. Otherwise the driver with the infraction gets posted for the penalty and has to serve it.
Denny should have been posted for jumping the restart and had to serve a pass-through, but since there weren’t enough laps, he should finish at the tail of the lead lap.