Motor 2 and 3 start at 1500us when arming in any flight mode

Hi everybody
I’m using an APM2.6 that i bought years ago from HK and it was in use in my Hexa without any problems. Now im upgrading to a PixHawk and want to use the APM in a DIY quad, so I installed the APM on my quad, cleared the EEPROM, flashed Ardupilot V3.2.1 via Mission Planner V1.3.70 and configured my hardware. I successfully calibrated the accelerometer. Aritificial horizon moves correctly in MP and motor test sequences CW starting front right. I think everything is configured correctly but when I arm the copter, regardless of the flight mode, every motor starts spinning at lowest speed, so far so good but when I give throttle motor 2 and 3 start at 1500us, so half speed. BTW this is all without props. When I roll the copter by hand arround 45 degrees to the right all motor speeds equalize so my conclusion is that the copter tries to roll to the right. Funny thing is MP shows correct attitude and as far as I can see the log shows that too.
Thank you all

2020-04-18 13-35-49.tlog (96.2 KB)