Downloadable items as a configurable option

I posted this on /r/magento2 and haven’t received any responses, so I’m posting it here as well.

We have a need for a user to choose from a simple physical product or a downloadable product (each with a cost/ price associated) via a single configurable product. Apparently, if you publish a simple downloadable product, there is no qty box. If it’s part of a configurable, the qty box appears. This seems like a Magento bug, but not 100% sure. We’re using a BSS commerce extension on the simple product to make the simple product have a dropdown (so the customer can choose between (for instance) 10, 20, 30, 40 units.

Have any of you come up with a good workaround for using simple and downloadable products as part of a configurable and not have the qty box appear on when the downloadable is selected?