As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 ENGINE OIL QUANTITY DECREASED TO 7 QUARTS ON TAKEOFF. REPORTS FROM THE TOWER INDICATED FLUID LEAKING FROM THE LEFT ENGINE. THE AIRCRAFT RETURNED TO MSP AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE OIL TANK CAP UNSECURED. THE OIL WAS SERVICED AND THE CAP WAS SECURED. AIRCRAFT RETURNED TO SERVICE.