Fixed, and it was a one-word bug with a wide blast radius. When a drop looks for the ground to sit on, the result was only accepted if it was greater than zero — so on every map whose floor sits at a negative world y, the game concluded there was no floor at all and left the item hanging wherever it spawned. Amherst is one of those maps. The check now tests whether a floor was found rather than whether it happens to be below zero. Re-test the boxes at Amherst, and if you get a chance any other map where drops looked wrong.