I had it a few time now that I placed something in a magic bag that was full, or just messy and the item didn't fit, and that the game put the item on the ground, sometimes even the next item that did fit I tried to put away to. I lost/almost lost some items this way, and one time this happened in occ and I had to ask a friend to get the item for me.
Usually there is a noise that the bag is full, so I don't know if this is a bug or not, but I do know it also happens if you get something true bartering and your inventory is full. (I know, the hard live of a merchant)
So my suggestion/request is: could there be a line, in capitals or even another colour, that states that you dropped a item on the floor?