Swarm Mystery

On May 1 '22 one of my hives swarmed and I collected and hived the swarm, which contained the old marked queen. Two days ago, May 15, the swarm itself swarmed! Again the swarm was collected and I have yet to to check for the queen. But having gone through the colony from which this secondary swarm emerged, I can find no queen cells, no queen, no play cells, nothing. Not even a virgin queen running around. How is this possible? Can a swarm ever leave a colony which has no viable means of surviving. I've been keeping bees for 50 years but never seen anything like this. Suggestions welcome. Can I re-unite the 2 parts of the original swarm?

So, if I am reading this right, 2 weeks after a swarm issued, the caught swarm then split into two with the old queen leaving the hive in which she had only been for 2 weeks?
Had she been laying in the period since she was hived? Is there food in the hive she came from? And what's happened since your post?