Single Direction Drift With Optical Flow On LPE

[MaMadDl]

Hello I have a Quad-Rotor With an slightly modified 1.6.5 (just to read analog sonar based On a PR from this repo) On a V1 hardware which has a RPi that runs an optical flow algorithm that i'm working on and an mb1240 sonar
i have ALT_HOLD working perfectly fine .
i couldn't switch to POS_HOLD Until i increased LPE_VXY_PUB parameter to 0.8
But When i switch to POS_HOLD, Drone always drifts Only in 1 direction. first i thought its my direction thats wrong which was based on this link :
https://dev.px4.io/en/tutorials/optical_flow.html .
after that i tried to align directions to NED Frame Still not working
here's my Log of last flight with Directions aligned on NED Frame : https://1drv.ms/u/s!AndghYiK3yPSgv93wqk0zd2RuqRU-w
The Odd Thing i noticed In middle of flight when i Switch from ALT_HOLD to POS_HOLD, Parameter LOCAL_POSITION vx and vy climbs to a random value and will not change until i land