The AOPA article (and the supposed executive comment) that the aircraft "applied full brakes all by itself" is rubbish. The A350 has no such system which automatically aborts a takeoff and applies brakes during a takeoff attempt...
The actual events and the cause were mentioned in the ppprune forums: the trigger was a database error in the Jeppesen Airport Map Database, which was loaded. Runway 22R at JFK has a displaced threshold, the database for the A350 did not properly consider this, hence indicated TORA for 22R (available runway length for takeoff) was too small. Once the aircaft accelerated beyond taxiing speed, the ECAM alerts "NAV ON TAXIWAY" and "T.O RWY TOO SHORT" were triggered. The pilots therefore elected to manually abort takeoff, since they were still far below V1.