hive spontaneously generating a bee

i had three hives, two of which had bees attached and were close together, and one further away with no bees attached, and no bees near it.
while i was near the third hive, the "bee enters hive" sound played, and then the "bees work" sound played a few times. the hive had no bees near it, so either it generated a new bee, or a bee somehow teleported in?