As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RADAR IN AUTO WITH WX+T SELECTED IS PAINTING A CONTINUOUS MAGENTA AND GREEN SPOT 40 DEGREES LEFT AND RIGHT OF NOSE. GROUNDED - YES. UNABLE TO DUPLICATE DEFECT. PERFORMED WEATHER RADAR BITE PER B737-800 FIM 34-43 TASK 801- INITIAL EVALUATION DID NOT CONFIRM FAULT. ACCOMPLISHED WEATHER RADAR OPERATIONAL TEST PER B737-800 AMM 34-43-00-710-802-001- ALL TESTS PASS.