When I make a request to the API to create a product without the SKU key, I get the error "resource: product, field: /data/sku, code: blank, message: attribute can't be blank, details: This field may not be null."
If I provide the key and set it to an empty string (""), it gives the same error. Putting anything in the string allows the product to be created.
However, from the Sell UI, you can leave the SKU blank and it adds fine.

How do I create a product from the API with a blank SKU? If I can't, this is a bug...