This is cosmetic once you know about it, but looks bad, and is confusing when you don't understand what is happening.   When you sell stacked items to the store, the number doesn't decrement properly as you sell each one.  i.e. if I'm selling three of something, like three stacked padded armors, it will show as three and not decrement to two as I sell the first one.  It updates correctly when you sell the last one, and shows that you have none left, and the sale works correctly except the count of items doesn't update to show them being sold.  

This can easily lead to selling more then you want to if you don't know that it's just an update problem, and even if you do know, it makes the game look like it's not working properly.