In Magic to Make the Sanest Man Go Mad, the USS Discovery and its crew were trapped in a time loop caused by Harry Mudd, and Paul Stamets was the only character who realized what was going on because of the influence of the spore drive on him.
“Filming it was like a wild episode because the notion of a time loop is a really fun and interesting notion,” said Anthony Rapp. “To be the only one who was aware of what was happening, filming it as an actor was like putting a puzzle together and figuring out, ‘Okay, how many loops have I done?’
“You keep trying to make it better and make it work. To do that domino effect, as an actor, it was almost like I was doing it myself.”
Source: Comic Book