Sitecore Experience Editor (SXA 1.8): Clone rendering not working

1. Clone a rendering from an existing SXA control, such as Navigation, to create a Mobile Nav.
2. Add it to the page. If it renders empty list items with no content, add the cloned control to the compatible renderings for that control.

For the Navigation rendering, update the compatible renderings under /sitecore/content/Sitecore/Storefront/Presentation/Rendering Variants/Navigation.