why did this game end as a draw?

why did this game end as a draw?

https://www.littlegolem.net/jsp/game/game.jsp?gid=2010075

I made a move setting up a winning endgame strategy, and it suddenly ended as a draw.

why?

I note that it was exactly 60 ply since the last promotion.  Perhaps that the point at which LG declares no progress.  It looks to me, based on a brief search, that the World Checkers Draughts Federation rule would be 80 ply.