Logic App role assigment for 2 containers in different Storage Accounts - bicep issue

Question

With Bicep we are creating a Standard Logic App.
We have existing resources:
FileStorage -> container
ArchiveStorage -> container

For the logic app, we are assigning 'Storage Blob Data Contributor' role assigments for both containers.
We are facing the following issue:

When we create the resources with Bicep, one assigmnt succeeds and the other one fails with error:
"Tenant ID, application ID, principal ID, and scope are not allowed to be updated."

If we change Role to 'Storage Blob Data Reader' for the one of the resources, they both succeed.
If we change one container name (different container names same role) -> it fails.

Any idea how to assign Same role, to different storage account containers?

Answer 1

We switched from

  name: guid(resourceGroup().id, principalId, roleId, uniqueString(resourceName))

to this:

  name: guid(resourceGroup().id, principalId, roleId, roleAssigmentName)

We gave the roleAssigmentName a unique name. And this seemed to work.
We could not solve though, why the uniqueString(resourceName) did not produce a unique value on every run?