As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKEOFF, THE FLIGHT CREW FELT VIBRATION AND HEARD A LOUD SLAPPING NOISE BY THE FORWARD GALLEY SERVICE DOOR. RETURNED TO MSP WITHOUT FURTHER INCIDENT. FOUND THE FORWARD GALLEY SERVICE DOOR SEAL OUT OF THE RETAINER AT THE UPPER FORWARD CORNER. REINSTALLED THE SEAL.