I think it has to do with someone logging out/exiting/hitting respawn/alt-f4 very quickly after death. Seems to me that someone logs/quits out right after death, the server doesn't save his body and loot to that position. Server reads and acknowledges he is dead but has yet to save the body. After that it treats it like he normally logged from the server, so poof goes the body. I can't say that is the exact issue. Reason I lean that way is at Balota I engaged in a fire fight, killed one man of a 2 man squad. I also died so I respawned to Balota and my body was still there. I never left the server, so the hive saved my dead character properly. My loot was still there. Just my two cents. Might test later.