I spoke with the produce manager at my local store, a couple years ago, when they went to fully automated re-ordering of produce.
Used to be, if he saw that something wasn't selling well, he could mark it down and try to clear it out. If he saw something was selling out really quickly, he could place an order and get more of it in, so they wouldn't sell out.
Now the computer does it all....and depending on who programmed it, and what setpoints they made on when something is re-ordered, it's usually either that the produce section runs out of something before the new order arrives, or they end up throwing out stuff that wasn't selling well, because it didn't get marked down quickly enough. The produce manager told me that with the computer doing all the ordering, he's throwing out more spoiled produce now, and running out of popular items more often than before.
Same problem might be going on at your Kroger's, with distilled water.