As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DESCENT INTO SAT A BURNT PLASTIC SMELL OCCURRED. SHUT OFF RECIRC FAN AND SMELL WENT AWAY. ON GROUND AFTER PASSENGERS WERE DEPLANED TURNED ON RECIRC FAN AGAIN AND SMELL RETURNED. TURNED OFF, SMELL WENT AWAY. NR 1 FAN IS DEFERRED ALREADY. DEFERRED NR 2 RECIRC FAN PER MEL 21-22-1. ENTERED INTO MM02. MXC NOTIFIED. UPDATE TO FOLLOW