deviceSetup failing to create customer under product specific ID

OK

The device I was trying to claim was not running the correct firmware, so I could not register it under my product.
I discovered this when I logged into my new user manually using particle-cli and could not claim, with a product id of 6! which totally does not belong to me.

I also discovered that customers with no devices registered do not appear under the customers tab in the dashboard under the product. This comment seems to confirm it as well: