"RetrievePrivilegesForUser, the user with id *** has not been assigned any roles, they need a role with prvReadWorkflow privileges"

Question

I have this flow which get called from a Canvas app inside a solution inside a dev environment, the flow calls 2 child flows, as follows:

The flow does not have any connection:

Now when some internal users call this flow from PowerApps by clicking on a button which has this formula:

'CreateApprovalItem(Elevated)'.Run(
    4064,
    "PPM-Admins-Test",
    "Work Order"
).response

they get an error

RetrievePrivilegesForUser, the user with id *** has not been assigned any roles, they need a role with prvReadWorkflow privilege".

All external users will get this error:

Any advice? I have other work flow which get called from PowerApps and it is working for all internal and external users, and those flows have connections (unlike the flow which is raising errors), and I am running these flows on elevated privileges using a service account, as follows:

Could the reason be that the workflow which is raising the error does not have any connections?

UPDATE: I added a test action to retrieve some SharePoint items inside the workflow, so the workflow get a connection reference to Sharepoint and I set it to run under the service account, but still I am still getting the same issue/error.

Thanks