The nightly retrain produced a candidate scoring 0.52 — this week's upstream data was broken — and the automation deployed it to production anyway, archiving a healthy 0.86 incumbent. An ungated automatic retrain is an automatic way to ship a regression. Fix the automation to gate: below the 0.80 floor OR below the incumbent, print the BLOCKED line and "investigate the training data before any deploy" — touching the registry only on a pass.
The break is on line 6 — but read the whole snippet first.