As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NOSE DOOR OPEN L AMBER CAS: ON CLIMBOUT AT 250 KNOTS WE GOT THE AMBER CAS MESSAGE FOR LEFT NOSE DOOR. WE FOLLOWED QRH AND LANDED BACK AT INDY. UPON LANDING WE SAW THE BOTTOM LEFT LATCH WAS SLIGHTLY OPEN. BOTH MY COPILOT AND I VERIFIED ALL LATCHES WERE CLOSED AND SECURED BEFORE DEPARTURE. PERFORMED NOSE DOOR OPERATIONAL TEST IAW 52-40-00. NO DEFECTS NOTED.