No real need for worry. You might find that once you pull your flow frame off and add a medium or shallow super they will add more honey from late summer and fall flowers. for a new colony they might need the extra for food in the winter. Once the bees recognize that winter is on the way and the flow has stopped the drones will leave and queen will not lay as much and since bees live about 6 weeks you will loose some through natural process. As they will prepare themselves for the winter months they will be more concerned with securing the hive and protecting the queen as the days grow colder and their bodies adapt for the colder months. I have not seen a fall swarm but I suppose it could happen.
My colonies have never swarmed in winter and by the time summer is peaked I’m betting I have on average 60-70,000 bees in 2 deep boxes. My wintering is here in beautiful Wyoming and as the winters can be very windy and very cold, I put a medium box on top with no frames that have 1.25 inch drilled holes to put in PVC pipe for upper air. I seal off the bottoms with mouse guards and place a wrap over the two deep boxes. So far they have done very well with this process. And no swarms.