In 2152, Archer blamed gremlins for a noise underneath the deck plating that wouldn't go away. T'Pol was confused by the statement, but Archer explained. (ENT: "Dead Stop")
It is strange that T'Pol seemed to be familiar with gremlins in 2151, and yet was unaware of them only a few months later. Conceivably she simply forgot or did not retain the information due to a disinterest in mythical creatures.