I have seen this happen a lot but until tonight it didn't really affect my gameplay.
Sometimes when you down a survivor they hit the ground and shift about 3-4 feet in some random direction. In two different games tonight however I hit a survivor before they got to the exit gate barrier only to have them slide halfway INTO it thus denying me a pickup and kill that was rightfully mine.
I dunno what is causing it but... please fix it. I can't be the only one who this has affected.