We have a premium Power BI instance which has a main semantic model which services 99% of reports using the standard live connection and this works fine for all users (including the specified RLS rules).
For design reasons, some of the Power BI developers have created composite models with some additional tables to utilise. These tables are manually entered and so there is still only one source for data but the report is in mixed storage mode because of the “design” tables.

This approach works fine for the majority of users but there is one user in particular which cannot view this “non-standard” type of report. When they open the report all of the visuals have the error “Couldn’t retrieve the data for this visual”.

A few other things to note:

• This user is a workspace admin
• The user can view live connection reports with no issue
• All reports and models sit in the same workspace
• If I browser as the composite model from SSMS as the user I can view fine