3376643 - Error "Missing Data for item xx: net value" occurs when creating billing item in the "Plan Customer Projects" app

When creating a billing plan in the contract preparation phase for a customer project in the "Plan Customer Projects" app, error occurs: "Missing Data for item xx: net value". If relevant settings are done in the incompleteness procedure, the sales order service can be created but its value is zero and this sales order cannot be edited.

SAP S/4HANA Cloud

The root cause lies in that the two fields are not filled in: "Amount to be billed" and the "Billing Due Date" when clicking into the billing item. 

Please fill in these two fields before saving the newly-created billing item: "Amount to be billed" and the "Billing Due Date" when clicking into the billing item.

Billing plan, Plan customer projects, Missing data, Sales order service, Zero , KBA , SD-SLS-PBS , Project-Based Services in Sales Documents , Problem

SAP S/4HANA Cloud Public Edition all versions ; SAP S/4HANA Cloud all versions