Alt hold and Pos hold

Hello experts,

I have some doubts regarding my quadcopter. I got nice flight on beginning and I started to test the parameter , failsafe setup. It began to misbehave.
When I fly in stabilize mode it suddenly go to RTL mode. I don’t changed mode but… I don’t know the reason. And also yesterday I setup radio failsafe.
( Throttle min value is 982- max value 2006 ) .
I tested it, by flying it and turn off radio. It started to land. But two motor on right side increased their power automatically and crashed. I have some question based on this. Dear experts if you would please help me.

FW : 4.0.7
920kv motor with TBS 500
10inch propeller
N8m gps.
30a esc.

  1. Do I need to re calibrate ESC and rc calibration after motor test?

  2. Is motor test or throttle hover. Which is better.?
    ( after I motor test. My drone fly very gentle hover in 50% throttle same when I set throttle hover… Is this same ) .

3 ) I setup EKF failsafe, but when I fly in Atl mode is began to descend.

if I tell any mistake above please tell I will clear it. I am. Just a beginner. Hope you understand

Post a link to the .bin flight log file where you experienced this.