I changed SKU for my product, but the old SKU still shows up. What is wrong?
Check if your product has “variants”. The base product SKU (the one specified on the “Product details” page) always differs from the SKU values for variants. Generally, the SKU values for variants represent the slightly modified SKU of the base product. If you search for such a product, it will show the SKU of the default product variant, not the base product SKU. Make sure you change SKU values for variants, not the base product SKU.