if you use mega items and throw or drop a weapon and then pick it up , it disappears forever if you have alchahol or molatovs in your inventory, because it really does duplicate them so the game sees your inventory as being full : (
solution is to drop all of your weapons before using the option and then pick them back up after.
i have no way to disecern the items. if this is too much of a problem then i will remove the option all together-
best,
Cal