Users are experiencing inconsistent behavior when generating vendor payment journals via payment proposal. Specifically, transactions for the same vendor are not always grouped consistently:

• In some cases, multiple invoices for a single vendor are consolidated into one payment line with a single voucher.
• In other cases, the same type of transactions is split into separate payment lines, despite belonging to the same vendor and following similar processing steps.

This inconsistency appears to occur under similar functional conditions and could not be reliably reproduced in a standard environment, making it difficult to identify a definitive root cause.

From a business perspective, this behavior does not block the process but introduces avoidable complexity and ambiguity in daily operations. Improving consistency or providing clearer, deterministic grouping logic (or visibility into it) would significantly enhance usability, reduce manual effort, and improve overall efficiency in vendor payment processing workflows.

Expected behavior:

The system should apply consistent grouping logic for vendor payment journal lines based on clearly defined and predictable criteria, especially when transactions share the same vendor and similar attributes.