Yoy may want to keep a nuc box handy in case one of your hives throws a swarm. It would be a shame to lose them if it happens and you have a chance at catching it.

That happens to beginner often because they have not experinece when to get new room for bees. If bees hive small hive with honey swarm escape without warning. When it seem that one box is occupyed, you may put second box lowest under brood box. So brood area is warm and colony can enlarge into lower box.
Otherwise it is quite impossible that small nucleus will swarm in same summer.