As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: COCKPIT DOOR UNLOCKED IN FLIGHT AND WHEN POWER WAS SWITCHED TO APU GEN. WAS ABLE TO CLOSE DOOR AND IT RE-LOCKED. CHECKED HISTORY AND FOUND UPPER AND CENTER STRIKERS TO HAVE ALREADY BEEN REPLACED, FAULT STILL CONTINUED. MAINTENANCE REPLACED COCKPIT DOOR LOCKING CONTROL UNIT IAW AMM 52-51-14 & TSM 52-51-00.