As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE ALTITUDE, THE CREW CONTACTED MAINTENANCE TO REPORT CABIN ALTITUDE FLUCTUATIONS OF 1000 TO 2000 FEET. THE CREW MADE THE DECISION TO RETURN TO MSP. THE FLIGHT DESCENDED INITIALLY TO FL250 AND THEN AGAIN TO 10,000 FEET AS A PRECUATION. THE CABIN REMAINED PRESSURIZED DURING THE AIR RETURN. THE FLIGHT LANDED WITHOUT INCIDENT AND WAS NOT OVERWEIGHT.