If a can of peaches is stored in a cooking pot placed on the ground, while my remaining inventory is full, the acto of opening the peaches will cause them to disappear. More simply, if my inventory is full, and I come upon a can of tuna, opening it while double carrying a weapon will cause it to disappear. Most common with canned food, but sawing a shotgun will also make it disappear, rather than fall on the ground.

This is probably related to new function of immediately replacing the item held in hands, when acting on another item; such as drinking or bandaging with a double-carried weapon in hands. The gun appears in vicinity until animation is complete, then item is replaced in player's hands. Opening a can of tuna while holding a gun in hands will cause the gun to take the place of the tuna in the vicinity screen.