Power BI App: no usage metrics?

I found a solution through trial and error.  The key is to remove the page level filter on the report name from the generated usage metrics report. 

As it turns out, the reports in workspace and the shared report in the app have different report IDs.  The default filter only selects the report in the Workspace for viewing.  If we change the filter on the usage report we will be able to see the usage of either or both instances of the report.

These are the steps I used:

1. From the report listing in the Workspace, click the metrics button to the right of the report to generate a usage metrics report.

2. Save the generated report by selecting File -> Save as

3. Open the saved report and select Edit Report (You won't be able to do this unless you save the report first)

4. Examine the page level filter (or was it the report level filter?  I can't remember exactly) and adjust/remove it as appropriate

5. Further customisation of the report is also possible

Hint: There is a table called "Reports" in the dataset, which has two fields: "DisplayName" and ReportGUID".  If you have published the report to an App, a new GUID is created for the App version but the display names of both the Workspace and App versions remain the same.  Furthermore, Power BI also keeps tracks of usage metrics reports by assigning them GUID's respectively.  In order to identify them, a quick trick is to add a Table visualisation on the page, and drop both fields from the Reports table on it.  With this insight you can set a filter by the appropriate ReportGUID.

I hope this helps someone, because it will make my hour spent on fiddling around this issue more worthwhile :).