Another post: https://community.safe.com/s/question/0D54Q00008is1jiSAA/why-is-the-download-url-not-being-returned-in-an-fme-server-app has already asked this question, but to date there was no definitive answer yet on that forum.
I included the "data download" during publish, so that is not the issue. It's just weird that the download link is not available in the workspace app, but is available when running the workspace from the workspace repository. Does anyone might know what the cause of it is?