Slight higher idle throttle when first arm?

I observed that, the px4 gives slightly higher throttle when first arm, then it is true idle throttle afterwards.

When I arm at first (first arm after power cycled), PWM output is around 1200uS.
This is measured by SERVO_OUTPUT_RAW.servo1_raw to 4.

But if I make throttle low couple of seconds, it become 1075.

PWM_MIN = 1075
PWM_MAX = 1950

i also have observed this

I’m not 100% sure but this could be related to the minimum throttle applied by the position controller when the landing detector detects takeoff. Check the parameters MPC_THR_MIN.