As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LGA - FL 1703 - WHILE ON APPROACH TO RUNWAY 4 AFTER PASSING 1,000 FEET, BOTH CAPTAIN'S AND FIRST OFFICER'S LOCALIZER HAD A FULL RIGHT DEFLECTION AFTER BEING ON CENTERLINE. A MISSED APPROACH WAS EXECUTED. THE NEXT APPROACH WAS NORMAL WITH NO PROBLEM WITH THE RECEIVERS. MAINTENANCE PERFORMED A SATISFACTORY FUNCTIONAL CHECK OF THE ILS SYSTEM PER THE R5 CARD. (X)