A320 captain reported a rejected takeoff due to asymmetric engine thrust.

Narrative:

Upon runway entry first officer was the flying pilot. Power was applied and noted that both engines started to spin up together. At that point the first officer put both levers into the flx position. As he was making the call for 'check thrust'; I noted the aircraft was pulling to the left and requiring more rudder than usual. There were no warning or cautions. I checked the thrust and saw the left engine was producing flx thrust and the right engine was producing toga power. I checked both thrust levers were in the flx detent. They were and there was no aural warning to the contrary. I called reject and brought the thrust levers to idle due to the first officer having a hard time maintaining the centerline of the runway. I was going to let the aircraft roll towards the next high speed taxiway. After a lag of approximately 2 seconds the rejected takeoff (rejected takeoff) maximum brakes kicked in. Rejected takeoff checklist was call for and aircraft was taxied off the runway.the brakes heated up due to the maximum braking; approximately 325 degrees maintenance control was notified. During this time the brakes cooled back into the normal range and we taxied back to the gate. Contract mx performed tests in conjunction with maintenance control all of which were normal. We were re-released back to ZZZ and chose to do a toga takeoff. Normal takeoff and trust reduction with no problems.

Original NASA ASRS Text

Title: A320 Captain reported a rejected takeoff due to asymmetric engine thrust.

Narrative: Upon runway entry First Officer was the flying pilot. Power was applied and noted that both engines started to spin up together. At that point the First Officer put both levers into the FLX position. As he was making the call for 'Check Thrust'; I noted the aircraft was pulling to the left and requiring more rudder than usual. There were no warning or cautions. I checked the thrust and saw the left engine was producing FLX thrust and the right engine was producing TOGA Power. I checked both thrust levers were in the FLX detent. They were and there was no aural warning to the contrary. I called REJECT and brought the thrust levers to idle due to the First Officer having a hard time maintaining the centerline of the runway. I was going to let the aircraft roll towards the next high speed taxiway. After a lag of approximately 2 seconds the Rejected Takeoff (RTO) MAX brakes kicked in. RTO checklist was call for and aircraft was taxied off the runway.The brakes heated up due to the MAX braking; approximately 325 degrees Maintenance Control was notified. During this time the brakes cooled back into the normal range and we taxied back to the gate. Contract MX performed tests in conjunction with Maintenance Control all of which were normal. We were re-released back to ZZZ and chose to do a TOGA takeoff. Normal takeoff and trust reduction with no problems.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1618363
Time
Date	201902
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Component
Aircraft Component	Engine
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 174 Flight Crew Total 6207 Flight Crew Type 1021
Events
Anomaly	Aircraft Equipment Problem Less Severe Ground Event / Encounter Loss Of Aircraft Control