As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THROUGH 10.000', MASTER CAUTION DOOR WARNING LIGHT FOR RT REAR SERVICE DOOR UNSAFE. RETURNED TO DEPARTURE. FOUND HANDLE NOT SEATED PROPERLY ON LANDING. C/W OPS TEST OF AFT SERVICE DOOR IAW AMM TASK 52-41-00-710-801. OPS CHECK GOOD. INSPECTED AFT SERVICE DOOR NO DEFECTS NOTED.