some possible causes:
Auto-generation by Klikpajak: Some systems auto-generate or adjust fields like invoice numbers, sequence numbers, or internal identifiers on upload — even if the draft looks fine pre-upload.
Field Mapping Issue: If NSFP is mapped incorrectly during the upload or transformation step, it might shift the value.
Concurrency Issue: If multiple uploads happen close together, Klikpajak might assign numbers sequentially based on real-time system state rather than uploaded draft values.
It’s very likely that Klikpajak has system-side logic that modifies NSFP values upon final posting, regardless of the uploaded draft state. Checking their documentation or consulting their technical support should help clarify whether you should manage NSFP yourself or let their system handle it.