- The process-global debounce map was keyed by token ID, so a stamp from one test database suppressed a later write in another and turned TestBackendTokenPostgres red depending on order
- Each compositeGuard now owns a stampThrottle; the backend guard and the ResolveBackend guard of one activation share it, so a single-app binary still writes last_used_at at most once a minute per token
- TestTokenLastUsedThrottlePerGuard pins the per-guard isolation
