As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RADAR SHOWS GHOST RETURNS AT 70 DEGREES LEFT AND RIGHT OF CENTERLINE AT ABOUT THE 4 TO 6 NM RANGE. GHOST RETURNS APPEAR IN BOTH WX & WX+T MODES, IN AUTO AND MANUAL TILT, SHOWS ON BOTH CAPT AND F/O SIDE. GROUNDED - YES. REMOVED & REPLACED (WXR) WEATHER RADAR R/T AS PRECAUTIONARY REF B737-800 AMM 34-43-41, OPS CK NML REF AMM 34-43-00-710-802-001.