Yes, it could be fraud. Or it could be poor work done at the store. Database not matching produce stand signs.
Sometimes when buying vegetables or fruit in the supermarket I've found the number announced for one fruit didn't match what the scale printed when weighting it, so I didn't really know which label to attach.
If the stand with watermellon say: "choose key 23", and when you choose key 23 it prints a label for potatos what should you do ? Invent the number based on the product description on screen ? How do you know that's the correct
label ? There're often several kinds of potatos or tomatos or apples or whatever. Even different batches of the same variety could have different prices (and number).