3172706 - Why do I receive contradictory error messages for the Reference Date field?

Why do I receive contradictory error messages for the Reference Date field on an invoice or invoice reconciliation (IR)?

referencedate contract pricing term pricing terms fixed fee pricing term reocurring reoccurring startdate enddate masteragreement master agreement MA malineitem ma line item , KBA , migration source: knowledge@ariba , view invoice reconciliation , view invoices , contract-based invoice , error messages , migrated on: 2022-04-02 14:16:20 , BNS-ARI-INV-IR , Invoice Reconciliation , BNS-ARI-INV , Invoicing , BNS-ARI-INV-ACC , Contract-Based Invoices , How To