We often embed Power Bi reports from one app into the app of a different workspace, as it means we do not have to duplicate the report to have it in 2 different apps.
When you go to export data out of the visuals it appears to work and you get the success message but no file is ever produced. You can successfully export data from the embed link url but not from the report where it is actually embedded in Power BI.
'Sample Report' - report and dataset live in the workspace and app 'A'. 'Sample Report' is then embedded (using the app 'Embed report' - 'Website or portal' link) into the App of 'B'
It appears as though the data can be exported:
But no file is ever downloaded. I believe this may be an issue with the new app navigation rather than the embedded report itself due to the fact that I can download data from the embed link when it's not in the new app navigation.