As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW INFLIGHT T689/17DEC - NOSE LANDING GEAR WOULD NOT RETRACT AFTER TAKEOFF. RETURNED TO DFW AND LANDED WITHOUT INCIDENT. FOUND NOSE GEAR PISTON FLAT DUE TO DAMAGE TO STRUT CYLINDER. REPLACED UPPER AND LOWER NOSE LANDING GEAR STRUTS AND SERVICED. SYSTEM GROUND CHECKED NORMAL OPERATION.