It is expected that the product specifications admin will always render the correct values for the specifications of a product. However, this may not always be the case. The specification value can be returned blank in the admin as if it had no associated value. In addition to the visualization problem, if the user saves the product using product admin, the blank specification value will overwrite the original value

Open a product specification form and compare the value shown in the admin with the value returned by the API.

Manage product specifications via API