Puel was forced to substitute Vardy late on, with the England international heading straight down the tunnel to the dressing room.
Commentators at the time suggested that Vardy might be in need of a bathroom break, and the manager confirmed such suspicions after the match.
"Jamie was ill and he could not come back into the top game. He felt this in the second half. It was his stomach... he could not digest the penalty decision," joked Puel.
He was referring to a contentious decision when Rob Holding appeared to handle the ball inside the penalty area, while already on a yellow card.
"I didn't understand why the referee didn't give a penalty," Puel added.
"It was a penalty and a second yellow card and sending off. This situation can change the game."