Ardurover Skid Steering Calibration

So i’ve got Ardurover 4 running on my Pixhawk 2 with a Sabertooth 2x12 RC. But having some issues getting it to go in a straight line.

Made some changes in the PID settings according to this post: Waypoint navigation problem, what’s causing this?

Changes i made:
ATC_STR_RAT_FF from 0.2 up to 1 and even as high as 1.6
ATC_STR_RAT_P from 0.2 up to 0.8 (made it worse) lowering it a bit didn’t change the behavior
ATC_STR_RAT_I from 0.2 up to 0.8 (made it worse) lowering it a bit didn’t change the behavior

In manual mode there is no problem driving a straight line

Included a video to demonstrate the problem. Also attached the bin of that particular mission

https://filebin.net/7mj3ul2u2cw06jo4

Before changing any more settings would love to get some pointers on where to start tuning.

Thank you