The Grove Racing driver found himself among the lead group during the first safety car of the race, which led to an awkward exchange with Broc Feeney at the safety car line.
Feeney had pitted while Reynolds had stayed out, the former coming out of the lane as Reynolds rounded Hell Corner.
The pair crossed the safety car line almost at the same time, with Feeney very slightly ahead, before Reynolds blasted ahead of Feeney in the queue.
Race officials noted that Reynolds was under investigation before the restart, before slapping him with a drive-through for passing under safety car shortly afterwards.
He tried to redress with Feeney to avoid the penalty, but race control was insistent that he still needed to serve the drive-through.
That left Reynolds baffled, given he claims he had no idea who was ahead at the line and was relying on instruction from race control if he needed to redress behind the safety car.
"Normally you race to the line and [race control is] the judge," he told Autosport.
"This time they were just the executioner, there was no judge going on.
Source: Autosport