As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AUTOTHROTTLE DISENGAGED DURING FLIGHT WILL NOT RE-ENGAGE. GROUNDED - YES. NO CURRENT FAULTS. BITE HISTORY SHOWED MSG 22-31687 CHANNEL A RATE AND SPEED MONITOR ASM 1. CW B737-900 FIM 22-32 TASK 819 NO FAULTS GROUND VERIFICATION TEST PASS.