As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT DUCT LEAK AFTER TAKEOFF. RETURNED FOR LANDING IN PSP. CHECKED FOR DUCT LEAK IN LEFT WING INBOARD LEADING EDGE TO LEFT AIR-CONDITIONING PACK. FOUND LEFT AIR-CONDITIONING PRESSURE REGULATOR/SHUT-OFF BLEED LEAKING BLEED AIR. REPLACED LEFT PRESSURE REGULATING SHUT-OFF BLEED VALVE. OPS CHECKS GOOD.