What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS AUTOTHROTTLE OFF ECAM MESSAGE. UNCOMMANDED AUTO THRUST DISCONNECT INFLIGHT. REENGAGED SUCCESSFULLY. MAINTENANCE PREFORMED TASK 71-50-00-810-810-A LOSS OF THE AUTOTHROTTLE CONTROL ON ENG. 2 , STEPS 1, 2,& 3. NO FAULTS NOTED ON ENG 2 FADAC CHANNELS A & B AFTER TEST STEP.