As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAIN CABIN DOOR OPENED ON CLIMB OUT. INSIDE DOOR LEVER HAD NOT BEEN PLACED IN SECONDARY LATCH. THE ANNUNCIATOR PANEL LIGHT HAD EXTINGUISHED INDICATING DOOR WAS SECURE. GULFSTREAM AEROSPACE HAS DETERMINED THAT ANNUNCIATOR LIGHT MAY BE EXTINGUISHED WHILE DOOR LEVER HAS NOT BEEN PLACED IN SECONDARY LATCH.