I'd lost a game when my opponent didn't have sufficient material to win (they only had a Knight) when I timed out. I did have sufficient material to win (a Bishop and a Pawn), which is my guess to why this bug has happened (and how to reproduce it).
I checked the rules and indeed when one times out they don't lose if the opponent didn't have sufficient materials to win.
I checked the rules and indeed when one times out they don't lose if the opponent didn't have sufficient materials to win.