If the production order lines are populated with components from a BOM, the account defined in the WIP Account field of the BOM for the relevant component populates this field. If theWIP Account field for the relevant component is blank in the BOM, this account is blank, too.
You can manually update the account in this field before the production order closure. The value of this field is then copied into the Account Code field of the issue for production.
Field name: WipActCode.