I've put together some inventory and equipment menu screens and I've noticed that if an item is dragged out of an equipment box, it will appear in the game world. However, if an item is dragged out of an item box to the game world, the item will not reappear in the game world, pausing the scene does not show that a prefab was created in-scene for the dropped item. The same Drag and Drop settings are being used for both menu screens. All my items are checked as "droppable" as well (not that this matters since one item displays the two different behaviors based on which menu screen it is dropped from). "Drop on Ground" is also enabled in Inventory Settings, but that doesn't seem to have any effect on dropped items appearing in the scene, nor does changing the Layer Mask or any other option in this section - items will still drop correctly to the game world from the equipment box and will not drop from the inventory box regardless of these settings.
After some more playing, I notice that if I drop my item to the scene via my part box, AND I have another of the same item in my inventory, then the item will drop to the scene (it also seems to get partially clipped by the ground which is strange). It will however destroy the other item of the same type in my inventory. Again, the equipment box has the same drop settings as the other boxes, and "remove on drop" is not checked for any of them.
Not sure if this is a bug or if I am missing a setting somewhere.