Consider a scenario where a financial institution is implementing a new cross-border payment service adhering to ISO 20022 standards. The development team has created a Message Definition for the payment initiation, but an independent review reveals that certain fields within the message do not directly correspond to the data elements explicitly identified in the relevant Business Process Model for payment initiation. Specifically, a field intended to capture the beneficiary\'s secondary identification information, while potentially useful, was not a primary data requirement defined in the BPM\'s process step for beneficiary details. What is the most critical implication of this discrepancy for the successful implementation and interoperability of the payment message?