Never seen this before
Went to a yard today, BTW it's early summer here. There's a dozen hives plus 51 mating nucs. As I drove up I could see a swarm in flight so ran down to see which hive was swarming. The swarm slowly swirled down the length of the yard, and as it went, several of the nucs joined it. The bees came charging flat out out of several different nucs just as per a normal swarm, and all joined the swarm which settled on a bush. I hived it but didn't bother trying to sort out the virgins. These nucs were all given cells just over a week ago.
Didn't bother trying to sort out the queens in the swarm, just stuck it in a box they can work it out.
The problem might be I made the nucs pretty strong because we were having a cold snap at the time. Had a look in a couple they still have a enough bees I've marked the ones that swarmed they will get a new cell on tuesday.