bin log, will post in some time as my membership is still under evaluation....

Graphing rcout will give more clues !
Motor 1 or 2 , which had the derbies in it?

Posting in ardupilot Facebook group will get more response

Finished assembly with new F450 frame on Friday night.
Saturday was a clear day for testing and problem solved, flying beautifully. I changed one suspected motor and propos also.
Was flying good but in-air, suddenly front right arm cracked (cheap stuff from Amazon seller) from the point where motor base is connected to the arm.....sad.
Spare arm is as expensive as a complete set. Ordered another F450 frame but this time from Sun Robotics.
I understand, gluing with Araldite and then use a Glue gun will not last long and may give away any time!!!
So, couldn't dare to risk entire quad......

By this week-end, I am confident that I will be able to get all set to fly.
Will post few videos / pictures.

Thanks