A quarter in which schema entropy rate went negative on any sovereignty perimeter — the formal definition of maintenance lapse. Forfeiture events are documented in the posture forfeiture log with: which perimeter, measured entropy delta, hypothesized cause, corrective action taken, and measured outcome. Forfeiture events are the primary training data for causal modeling: which maintenance gaps cause which forfeiture patterns? Repeated forfeiture events on the same perimeter indicate structural maintenance insufficiency, not random variance. Forfeiture events make contested posture visible in the engagement record.