As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WITH A/P ENGAGED DURING DESCENT ERROR MESSAGE SINGLE FMS OPERATION. DISENGAGED AUTOPILOT NR 2. TEMP RESTORED NAV MODE THEN A/P NR 1 DISENGAGED, SAME ERROR MSG. SET FMS MASTER SWITCH YP FMC1. THIS ENGAGED BOTH A/P. RE-ENGAGED A/P NR 2. OPERATED NORMAL. BOTH NR 1 & NR 2 FMS OPS CHECKED GOOD PER MM 34-58-00. CHECKED NR 1 & NR 2 A/P PER MM 22-10-00. NO DEFECTS NOTED.