-Scope Organization supported for all Workspaces

I'm a Power BI Service Admin (via AAD Priv ID management), and I tried using this command to add a user to an orphaned workspace, but got hit with the following error:

WARNING: Only preview workspaces are supported when -Scope Organization is specified

Add-PowerBIWorkspaceUser : Operation returned an invalid status code 'InternalServerError'

At C:\Users\<username>\Desktop\<script>.ps1:7 char:1

+ Add-PowerBIWorkspaceUser -Scope Organization -Id x#xx####-#x##-###x-# ...

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  + CategoryInfo          : WriteError: (Microsoft.Power...BIWorkspaceUser:AddPowerBIWorkspaceUser) [Add-PowerBIWorkspaceUser], HttpOperationException

    + FullyQualifiedErrorId : Operation returned an invalid status code 'InternalServerError',Microsoft.PowerBI.Commands.Workspaces.AddPowerBIWorkspaceUser

Any idea when non-preview Workspaces will be supported? This would be an invaluable tool for saving my users lots of rework and cleaning up our Cloud Service tenant.

Start by reviewing the Add-PowerBIWorkspaceUser command's -Scope Organization behavior and the Power BI service support for non-preview and orphaned workspaces. Confirm the relevant API limitations and existing command tests, if present. Done means organization scope can add users to supported non-preview workspaces without the reported warning or internal-server error.