Hi @bonifacious
Could you please share a screenshot about your issue?
Do you want to populate a Dropdown box with values from the PowerBIIntegration.Data?
Further, could you please share a bit more about the data set you used in your Power BI report? Is it a Excel table?
Based on the issue that you mentioned, if you want to populate a Dropdown box with values from the PowerBIIntegration.Data, please take a try with the following workaround:
1. I assume that the Data set you used in your Power BI report is a Excel table, please consider add the corresponding Excel table as data source within your embedded canvas app. Then connect the Edit form to the Excel table data source.
2. Within your Edit form, select the field data card which you want to configure as a Dropdown box. Then edit field, expand the corresponding field, then switch the Control Type to "Allowed values":

3. Set the Items property of the Dropdown box to following:
[@PowerBIIntegration].Data.ColumnName
set the Update property of the field data card which contains above Dropdown box to following:
DataCardValue3.Selected.ColumnName
Note: The ColumnName represents the column in your Excel table, which you want to display within the Dropdown box. If above formula could not work in your app, please set the Items property of Dropdown box to following:
Distinct('Your Excel Table', ColumnName)
set the Update property of the field data card which contains above Dropdown box to following:
DataCardValue3.Selected.Result
Please consider take a try with above solution, check if the issue is solved.

Best regards,