## TL;DR

Large gaps between invoice date and posting date can hide period manipulation or stale invoices surfacing late. Flag invoices posted far after their date, especially around period ends, and require explanation: late vendor billing is usually innocent, but the pattern around closes deserves scrutiny. Keep the original invoice date immutable for the audit trail.

## Steps

1. Compute the lag between invoice date and posting date.
   Expected: A lag distribution.
2. Flag outliers, especially near period ends.
   Expected: Candidates.
3. Require a reason code for large lags.
   Expected: Documented explanations.
4. Review the pattern quarterly.
   Expected: Systemic vs one-off.
5. Keep invoice dates immutable; post to open periods.
   Expected: A clean audit trail.

## When to use

- Period-end monitoring
- Stale invoice reviews
- Audit preparation

## When not to use

- Period close execution
- Accrual accounting
- Payment timing

## Compatibility

ERP-agnostic.

## Variant phrasings

### invoice posting lag anomaly

### stale invoice period end

### backdated invoice flag

## Root cause

Dates are the easiest field to manipulate for period shifting, and late invoices are also just common. The flag separates the pattern from the noise.

## Edge cases

- Vendor billing cycles legitimately lag; learn per-vendor norms
- Corrected invoices carry new dates; link to the original
- Intercompany timing differences need coordination, not flags

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_n_OXZ6ftChVs4of97Vx1Gw