Obviously a 'different' 737 QRH
The intermittent cabin altitude/configuration warning
horn sounds and the TAKEOFF CONFIG lights (if
installed and operative) illuminate on the ground
when advancing the thrust levers to takeoff thrust.
VH - it is simple actually - old and dodgy reed switches on the LEDs. Air loads and vibration give 'unlocked' = Config warning @120kts. Had it several times.