I've recently bought a few potions/elixirs from SDBs at 'full' price only to find the item has been used.
I'm not sure if it is the same with powders. Haven't tried.
As on Auction, is it possible for there to be some indication of whether the item is New or Used on SDBs?
I know they currently stack regardless of new or used in the SDB (which is the problem when they are being sold) but maybe it could be that you can only stack the 3/5 Dung-Kicker (for example) in an SDB, full ones would stack in another, 4/5 in another, etc.
I was going to put this in Ideas, but it seems a little more than just that.
*Edited because I kept saying STB instead of SDB. One is a Glitch term, the other is something my doctor is looking into.