Hello there,
Strange bug. Game ended with everyone dying to someone else (my last plunder was WW, so I plundered him but he killed me). I had already plundered 2 players, died on the night of my third plunder, but game ended as a draw not a win for me. Yes, I died, but the wiki explicitly states that
"you don't need to be alive in order to win. If you successfully plunder 2 players before you die, you will still win at the end of the game, even if you died the same night you got your second plunder. "
And as I said, the night I died was my third successful plunder.