Service client Purchase Order from a punchout is missing supplier site

Summary:
When a service client BU creates an auto-generated PO from a Punchout catalog, the supplier site is missing on the PO.

Content (please ensure you mask any confidential information):

We have one Service Provider for 100+ service clients.
A Punchout Catalog has been created and a content zone. The content zone is available for all service clients (requisitioning BUs).

When a RQ is created for the Punchout as the service provider BU, the PO is autogenerated and submitted for approval, after the RQ is approved.
This PO is having Supplier and Supplier Site.

When an RQ is created for the same Punchout as one of the service client BUs, the PO is autogenerated but is missing the Supplier Site.