As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED THAT DURING DEPARTURE CLIMB OUT, CLIMBING THROUGH 3000' MSL (1700' AGL) "DOOR UNLOCK" CAUTION ANNUNCIATOR ILLUMINATED. THE FLIGHT CREW ELECTED TO DIVERT BACK TO THE AIRPORT AND LAND. THE MAINTENANCE VENDOR TROUBLESHOT AND ADJUSTED THE AFT BAGGAGE DOOR LATCH PER AMM. OPS CHECKS SATISFACTORY. THE AIRCRAFT WAS RETURNED TO SERVICE.