I have a newly installed package. There were a lot of dead bees in the package after 5 days of shipping. Unfortunately a lot of them found their way into the hive when I installed the package. The behavior you described is exactly the same thing I have seen in both of my hives. But sometimes they just push them off the edge and others they jump off to the ground with them and fly back to the hive. This morning I noticed a couple dozen dead on my patio. I guess that is the new dumping ground.