"Export to Mac" file opens up to nothing

Have you searched the Docs and Knowledge base? Yes
Principle Version: Version 5.9 (5020)
macOS Version: 10.14.6
Sketch Version: 60.1
Description of what you need help with:
Client downloads the exported file from DropBox and unzips it to find there’s non-usable content in there. Basically, can’t user test this.

Steps to reproduce the behavior:

  1. From Principle, Export to Mac
  2. Upload the file to Dropbox for client to download
  3. At this point, in the Dropbox, the file has an extension (.app) added to it. Example: prototype-file.app.
  4. Client downloads it and realizes it’s now a zip file: prototype-file.app.zip
  5. Unzips it and finds a folder named Contents… but no movie nor way of using it. Screenshot below.

Screenshots/Sketch File/Principle file: https://www.dropbox.com/s/oyi097ttp94b1ew/principle.png?dl=0