Helo Patel,
Well if you able to do customer return correctly then all pre-requisites are covered.
Refer the help document for reference - gives help on a scenario
Customer Return Processing (in Inbound Logistics)
Customer Returns Processing
Third-Party Order Processing — Customer Return
Business Scenario: Customer Return Management
maybe check if the inspection plan is correctly set and if you are still facing issue create an incident to us as we need to check your configuration.
Regards
Leo