I'm betting it's inventory turnover (e.g. busier stores). It sounds like they were have problems with the inventory management component of SAP keeping up with the rate and volume of transaction that they were putting through it.
In the context of a retailer, "high turnover" means that individual products spend very little time on the shelf before being sold, and they are replaced with new products very quickly. For LIDL that means places where they have very busy stores. These places are "lucrative" because they are busy, but are not at all "high profit" - they sell products with extremely small profit margins.