Persistent 422 (Unprocessable Content) error when adding to cart

[Ashfaq]

Hey, this is a fairly common issue and the Shopify team is already aware of it. There’s also an active thread about it that’s been ongoing since last year.

Ajax API returning 422 even when items are in stock. Works fine in incognito

Many merchants are having a problem where the add.js endpoint shows an “Out of Stock” error, even though the product is available. The issue doesn’t happen in incognito mode and works fine after clearing the cache. However, more complaints are coming in because customers are also experiencing this problem. Is anyone else facing this?