Walmart unit price is completely broken in general. They also have glitches in the “did you forget to add?” page where it will show an item as a sale price, but when you add it, you’ll see total price increase by sale price, and a few seconds later, a second price increase to the normal price. Re-checking the cart will show the item as not on sale. There are some other real weird glitches with that e-commerce platform. A rat’s nest of bugs that might not be intentionally nefarious, but also could be.