Late payments start
Invoices that were always paid on time start arriving 15+ days late. Payment behavior changes before anyone says the relationship is strained — money moves first.
Detection logic
Track days-to-pay per invoice per account vs its own history. Flag the first 15+ day late payment after 4+ quarters of on-time payment.
When it lies to you
AP system changes, new finance leadership, or fiscal year-ends delay payments without meaning. Check whether the delay is process or intent.