Until inventory systems manage on-shelf stock levels separately from back-room stock, the problem will never go away. You can only sell from shelf stock, but most retailers only manage "balance on hand" which leads to off sales, inaccurate demand assessment and the problems shown here. There are answers!

This is the best summary of the reality of store inventory visibility and accuracy, or, rather absence thereof I have read, and the perfect description of the current situation in most grocery stores worldwide.