That type of draw has to be claimed, it is not automatic. Triple-repetition of position and 50 move without captures or pawn moves work just like they do in OTB chess where you have to claim it.
https://support.chess.com/customer/en/portal/articles/1444798-how-do-i-claim-a-draw-
I'm playing a game with a guy who won't accept a draw. We're in an endless three move loop. Will it ever be officially drawn?