Two laying queens in one hive in October — mother and daughter both laying, leave them or intervene before winter?

Kent, third year, five colonies. Did my last proper inspection on Sunday in a warm spell and found something I've only read about: two laying queens in one hive. My green-dot 2024 queen was on one frame laying away as usual, and two frames over an unmarked, larger, glossy young queen was doing exactly the same thing. No fighting, bees completely calm about the whole arrangement, eggs and larvae everywhere. I'm assuming this is a supersedure and the daughter got mated in the September weather. The books say the old queen is usually got rid of over winter and the colony sorts itself out. But my instinct is to DO something — take the old queen into a nuc, or pinch her so there's no confusion. It's October though, and I can't make a nuc that would survive. So: leave them and trust the bees? Or intervene while I still can? Nothing about this colony looks wrong, which is almost what's bothering me.