Governance

# Incident Post-Mortem: Causal Drift in Payment Routing
**Incident ID:** INC-2025-0417
**Date:** April 17, 2025

## Executive Summary
A causal drift in payment routing logic led to intermittent 504s for 18 minutes, affecting ~0.82% of transactions. No data loss or financial inconsistency.

## Timeline
• 09:12:03 Drift detected in causal simulation (deviation > 3σ)
• 09:14:47 Alert escalated to on-call.
• 09:19:02 Rollback initiated.
• 09:30:11 Traffic restored to baseline.

## Root Cause
Routing weight update did not account for downstream latency distribution shift introduced in v0.7.1.

## Resolution
Rollback to v0.7.0 and added latency-distribution guardrail.

## Impact
• Affected: 2,341 transactions
• Failed: 19 (0.82%)
• Duration: 18m 8s
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