We are experiencing issues with our CSM Contact user’s ability to see Cases on the CSM portal.
Custom business rule implementation.
The behavior is seen as the user does not have access to the case record. The user does not have access to the record because of the custom business rule implemented. This script checks a custom field on the case field. This business rule appears to be failing, hence the user does not have access to the case.
Disabling the custom business rule, and reverting 'Case query for customer' the out of box business rule back to base code resolves the issue:
This checks the out of box Contact (contact) field on the case form. When the Contact field is being used with the out of box business rule 'Case query for customer', the user is then able to see the case record as expected.