SYNC.php was silently closing/locking any open session that called it (orphaned open_systems table trusted as truth). kill-switch.html was guaranteed to fail CLOSE.php's session_log_gate every use since it never called save.php first, silently degrading to a COMMS-only fallback -- the real cause of Travel[95] being stuck open 3 days. Both root-caused via direct source reading, not guessed at; both verified live before/after, not just deployed on theory.