When a player is standing on a structure that is above the game floor, items that are set on the ground (namely bullets, sometimes other things), there's about a %25 chance that they will clip through the ground down to the game's floor.
Example: If one stands on the second floor of a building and empties a box of bullets onto the floor, they will occasionally clip down to the next floor or even lower, making the item irretrievable.
This is running the latest stable build (0.32.114557) via Steam on a Windows 8 64-bit Laptop.
I have yet to test it with the latest experimental build.
I have had all kinds of items either inaccesible on being found (on top of dresser or otherwise unreachable) but many times I had to put down an item briefly (or just cancel my click-drag to scroll down so I can reach bag space) and it will move to a place where it is stuck in a wall, floor, other object, or just otherwise out of reach. I have also fallen through the floor myself numerous times in the same building model (a dark wooden residential house with stairs to access at both ends and an inaccessble ground-level basement and generally contains no loot at present). Maybe expanding the loot radius would help
I had an issue when i looted a dead bodies Backpack on the second floor of a school building. After dragging the new backpack over my char it was attached to my back (even though the char animation showed it lying ON my feet)
Thing was, that my old backpack with my stuff wasnt in the vicinity area and could not be found anywhere near the looted body. When i finally gave up searching for it, I found it a floor beneath lying on the ground, whils exiting the building.
(This was in Elektrozavodsk)
This has been reported previously - make sure to search before opening new issues.
I am closing this as duplicate of #0000018: Dropped Loot (dropping through floors.)
Please vote up the original issue to increase visibility, and add any extra information in the notes section.
Thanks