To Geez: I have seen this on a couple different servers now. I have also noticed this has to do with the UI system when exiting the inventory screen with any bag/container in your hands. Whatever item your white square Is hovering on will be placed into the held bag/container (if there is room) when you press B to back out of the inventory screen. If you back out using the select button (Inventory button) it does not seem to happen. Also happens if white square is on items in vicinity and you press B to back out.