Mixed Mode Dataset issues - Cannot load the data for this visual

Hi all,

Hopefully someone has some experience working with mixed mode datasets.

I have a mixed mode dataset deployed to the service, a report over this works fine for me, however everyone else recieves errors on all visuals 'Cannot load the data for this visual'.

Workspace is on premium capacity.

Dataset A is Import mode consuming data via a on prem gateway (Test user is assigned read & build permissions)

Dataset B is Direct query to Dataset A in the service with some additional data from on prem gateway (Test user is assigned read & build permissions) connection to Dataset A is via a shared cloud connection with Azure SSO enabled.

Test user access's via App and has read access.

Tried many things and cant crack the issue, any help greatly appreciated!