When you drink a soda without putting it into your inventory first (mousewheel over the soda and choose drink, or right click in vicinity and choose drink) once you are done drinking it an invisible soda can will be placed in your inventory and will take up one slot and cannot be removed unless you log out and back in again.
- Legacy ID
Simply mousewheel over a soda can and choose drink instead of picking it up while having an empty space in your inventory. The empty space will be occupied by an invisible soda can which cannot be removed unless you log out and back in again.
Confirmed happening to me as well.
Drank 4 or 5 sodas while walking around and I couldn't figure out why I had so many bugged (apparently empty) slots that I couldn't use in my inventory.
When I logged off and back in I found all sorts of empty cannery in my bags.