As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CABIN ALTITUDE BEGAN TO CLIMB FOLLOWING A MUFFLED REPORT. AIRCRAFT WAS IN CRUISE AT FL330 WHEN MASTER WARNING ILLUMINATED AND PRESSURE LOSS BEGAN. CREW INITIATED AN EMERGENCY DESCENT TO FL100 WHEN CABIN PRESSURE GRADUALLY RECOVERED. FLIGHT CONTINUED TO A NORMAL SAFE LANDING AT MSP. MAINTENANCE FOUND A BLOWN DUCT OFF THE LEFT WATER SEPARATOR AND RESECURED IT. OPERATIONAL CHECKS WERE ALL GOOD. AIRCRAFT RETURNED TO SERVICE.