SAP S4 Hana Service - Contract determination error at Service Order level

Hi,

I have created a service contract and have released and billed it. While creating a service order, the respective contract is getting determined correctly as a pop up but upon selecting the right contract, but system is giving an error message.

Contract# 5000000023 is determined in the service order correctly as a pop up selection

But upon selection, getting the below hard errors

** I have entered the same reference object (Equipment number) in contract and in the service order.

** I have used contract determination as D in service order setting.

Is there a bug or system config missing?

Silvia Ventura if you could help here?