As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BEGAN TAKEOFF ROLL, AT APPROXIMATELY 50 KNOTS, A TRIPLE CHIME MASTER WARNING WAS HEARD ACCOMPANIED BY A RED EICAS SPOILERS EXTENDED MESSAGE. NOTICED SPOILERS WERE EXTENDED ON FLT MFD PAGE AND PHYSICALLY FELT THE LIFT DUMPING. ABORTED TAKEOFF. THE SPOILERS STOWED ON THEIR OWN DURING THE TAXI BACK.