@b.sean as @ssh4 said, this is our "draft mode" feature; it allows you to upload models and customize them without anyone except you being able to see the model URL.
Sadly, all our exporters do not offer the option to publish/keep draft and this is the case for the Substance exporter.
We are working towards offering a more consistent user experience everywhere. In the meantime, if you if this is a real issue for you, you may export your substance textures manually and then pack them in an archive you upload directly on sketchfab website. The drawback of doing thisn is that you'd have to rebind some textures manually.