Dear Long,
I think you have two partner functions with category 0008. But this is not possible, please see note 844503 for this. You can have only ONE person responsible!
This is hard coded in table CRMC_PARTNER_PSA. Here the system table restricts this partner function cat. 0008 to be unique. Check the field "TYPE UNIQUE" in the table.
I hope this information and note will help you !
Best regards
Rene