As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NOSE GEAR REMAINED DOWN AND LOCKED AFTER SELECTING GEAR UP AFTER TAKEOFF, RECEIVED GEAR DISAGREE WARNING MESSAGE. AFTER RUNNING QRH PROCEDURE NOSE GEAR RETRACTED. INTERROGATED PSEU, NO FAULTS LOGGED IN MEMORY, NO CURRENT FAULTS. PERFORMED OPERATIONAL TEST OF LANDING GEAR EXTENSION AND RETRACTION SYS IAW AMM. COULD NOT DUPLICATE PROBLEM. SYSTEM OPERATES NORMALLY.