This fixes that fail diagram describes how people often address symptoms, but not fundamental causes. Poke yoke is a design principle that operates in one of two ways. One is to prevent the defect from occurring, which addresses the source. This is ideal because there are no defective products to scrap or rework.
The other is one that prevents defective work-in-process from being passed on to the next stage. This does not prevent the defect from occurring. There is still the scrap and rework, but it prevents the product from reaching the customer.