Dyanmics 365 Sales - Power BI TIle Dashboard - This Content isn't available

Hi,
I'm running into an issue where some of our users require extra permissions in order to see Power BI Tiles in our Dashboards. 

When Users are unable to see the power bi tile they get the message "this content isn't available". Also this isn't just occuring with new users, this originally started with a user who had been using a report for months, and suddenly had this error message. For the moment I've been assigning the "Power Bi Workspace Viewer" security role as a workaround, but this seems to be an outdated way of sharing reports?

Our workspace has an embedded license, all of our users attempting to view reports have the viewer role in the power bi workspace, and each user has had the dashboard shared to them with the read/write privledge.

So what I'm looking for:
1. What roles do users need in order to view the Power Bi Tiles in Dynamics 365
2. Is there any official documentation outlining user permissions needed to view Power Bi TIles in Dynamics 365 Sales
3. If assigning the Power Bi Workspace Viewer role is intended, how/why are some users able to access reports without this role