Maybe doesnt happen just in hills, but me and my friend just took out a crew of 4 in the North long hill outside Elektro, and their bodies started flying down to the bottom of the hill and some loot was bugged and we couldnt drag it off, only solution was to put the items in your backpack then throw it on the ground.

Weapons were not available to trade or throw out of the corpses.

Loot was lost :(