FDRSM-5
Failure Case Catalog
When “stable” can still be governance-unsafe

Named Failure Cases

A stability label is not a blank check. This catalog documents cases where mathematical stability exists while governance risks emerge (overreach / underreach / oscillation).

F1 — Stable-but-fragile trap
λ < 0 (stable) but |λ| is small and Δ is near zero.
Risk: minor drift flips regime; decisions become brittle.
F2 — Proportionality collapse
k is far above boundary (very stable).
Risk: governance overreach becomes structurally unjustified even though stability improves.
F3 — Oscillatory posture switching
boundary drift causes frequent near-boundary crossings.
Risk: governance posture flips repeatedly; trust and legitimacy degrade.
F4 — False certainty band
α and β uncertainty is ignored.
Risk: the model appears deterministic while confidence bands are wide.