Unit Configuration installation issue

Good Day All,

We have an issue with creating Unit configuration.

Business case is like the customer receives the order and he creates a BOM for that order and using manufacturing work order he builds the order.

Once the Manufacturing is complete Instance are created in Install base with parent child relationship as per the BOM.

Master Configuration is created in CMRO and its similar to BOM in previous case (Parent Child Relationship).

A Unit configuration is created from the MC and the instance used is the Instance created during Manufacturing.

The top node gets installed and the UC header is created, but the child instance do not associate to child positions in UC (the instances do not show up in the UC page - child position)