Steps to Reproduce
1. Go to Site Settings -> Content -> Documents and Media
2. Add a new Document Type
3. Add a text field and make it required
4. Create a new folder
5. Edit the folder
6. Under Document Type Restrictions and Workflow select the Document Type created in Step 3
7. Go into the folder
8. Click on File Upload and upload any file
A document type valid for the folder is used by default and the document can be published successfully.
The Basic Document Type is used by default and publishing the document fails with a generic error.