I think the best approach depends on this. It they are part of your swinging circle, then I would probably try to clear the air by pointing out how the mixed signals led to what happened. Not in a "so there!" sort of way, but just getting things out in the open to talk about them. That may make things better, but it runs the risk of making them worse too, and you'll just have to evaluate what the worse part of that equation would mean for you if it goes that direction. One way or another, it will help deflate the elephant in the room that is probably always going to be there if y'all frequently encounter one another.
If they are someone you rarely if ever expect to encounter again, then I would just leave it right where it is.