So some days ago i was selling summoning rocks in my shop in 50stacks and i had 100 summoning rocks on each slot. When i tried to get back the summoning rocks it only gave me 2 summoning rocks (as if every stack was one item). I asked a friend and the same thing happened to him but since he sold in 100 stacks he only got one item back. Fortunately i got my rocks back from gm but i dont know if the bug was fixed. When i tried to put summoning rocks after that point on, it was impossible to even put them for sale on the shop. So thats two diferent bugs, please look into it and reply when it has been fixed or if i am maybe doing something wrong...
I've personally never been able to put more than 99 of an item into my shop in a single stack. That might be what's going on with your summoning rocks at the moment, because I saw some for sale earlier today.
You can put 99 in for individual sale, however you can put 100 (or x amount) in as a bundle and sell the 100 all as "one" for a bulk price (not for individual sale). That seems to be causing the issue, since by the sounds of it they've put in two bundles of 50 - and the server is reading those as only two items, not 100... Unless I've completely misread this whole thread. Lol. IN ANY CASE - Have you tried closing your shop down and re-opening it? Maybe it's glitched?
