As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PULLING THE POWER TO IDLE DESCENDING FROM 10000' WE HEARD A LOUD POP AND THE CABIN PRESSURE DUMPED. CABIN DIFFERENTIAL REMAINED AT ZERO AND THE CABIN RATE OF CHANGE FOLLOWED WHATEVER THE PLANE WAS DOING. OCCASIONALLY THE RATE WOULD FLUCTUATE +- 200' WITH CHANGE OF POWER SETTING BUT WOULD RETURN TO THE RATE AT WHICH THE ACFT WAS DESCENDING.