With swarming, it's never just one or two cells, it's many cells, in a crowded hive. With only one or two or three cells, it's usually supercedure. This happens sometimes with packages. I can only guess it may be because of an inbalance of the ages of bees in the package, maybe too many nurse bees waiting on the queen to start laying enough for the nurse bees to be happily busy. Or maybe something else. The bees in the package are no relation to the queen and they are of a shaken bunch of bees into a large cage and then dumped into a small cage with a caged queen inside. Sometimes they tend to try superceding the queen, sometimes they stop the process themselves before it completes by tearing down the cells they started. Sometimes they don't and they replace the queen.