This could happen with Double Agenda in effect. For example, in a 2-player game, if the goals are Star Gazing and Time is Money. Player A has The Eye and Time in play while Player B has The Cosmos and Money. Player A plays Exchange Keepers and exchanges The Eye for Money. Is the game over, with two winners, or must it continue until one and only one player has a winning condition?
This could also happen with 10 Cards In Hand
A: You would keep playing until only one player currently meets the win condition.