Skip to content
KSEF-BUS-197 HEURISTIC Warning KSeF Guard Only

Invoice issued on weekend

Faktura wystawiona w weekend

Problem

The invoice has an issue date (P_1) falling on a weekend (Saturday or Sunday). Weekend issuance is rare and may indicate a date entry error or an automated process.

How to Fix

Check the invoice issue date — invoices are usually issued on business days. If the date is correct, this may be justified by a special business process.

Source Reference

KSeF Guard heuristic (weekend invoice issuance — gateway validation practice)

View source PDF

Source Quote

“Invoice issuance on weekends (Saturday, Sunday) is unusual and may indicate a date entry error or automated process without human review.”
Description SHA-256: ff9d153bec86…

Justification

BUSINESS LOGIC

Legal Basis Chain

1

KSeF Guard heuristic — weekend issuance

KSeF Guard heurystyka — wystawianie w weekend

“[KSeF Guard heuristic] BUS-197 has no direct basis in the VAT Act — Art. 106i regulates the issuance deadline (by the 15th of the month) but does not distinguish business days from weekends. The rule is an operational heuristic that enforces the practical pattern of issuing invoices on business days — a weekend issuance often signals a date error or an uncontrolled automated process.”
KSeF Guard heuristic (business-day issuance pattern)