Magento does not support '/' in the Product SKU

There is a known bug in Magneto #8615 where some Magento API endpoints reject API calls for products with a '/' in the SKU.

This is a known issue in Magento:

This causes Spark Shipping not to be able to make API calls for products with an '/' in the SKU.

Magento's recommendation to correct this issue is to remove the '/' from the SKU.