As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A/P ENGAGED IN COMMAND B LEVEL FLIGHT FL330 DISENGAGED WITHOUT ANY REASON IN SMOOTH AIR, ACFT WAS TRIMMED. ENGAGED COMMAND A AND CONTINUED WITHOUT FURTHER PROBLEMS. ENGAGED COMMAND B ON DESCENT, WORKED NORMALLY. ACFT GROUNDED. PERFORMED FIM TASK 22-11-00-810-801. DFCS BITE CHECK AUTO PILOT CHANNEL A & B. ALL AUTO TEST PASSED.