Classic PO Creation with Bidder added items

Dear Experts,

            We are using SRM Bid Decoupled scenario. The Bidder logins to SUS system and responds to RFx. I have maintained the product category

in the SUS system.

Consider a scenario,  A RFx respondent will login to SUS --> access RFx--> Create Response --> Add few item (Item type : Material) in the RFx response, wit mentioning only Product category, UOM, quantity and price.

When such RFx response is being awarded with PO, the Classic PO is failing in the ECC with error "Enter Material or account assignment details"

Is this the standard feature in Classic Bid Decoupled Scenario? Is there a way to avoid this?

Thanks,

Krishna