Tractor steers better in one direction than another

Currently running AIO v2.5 dual with a Hydraforce valve. AOG v5.8.3
Having been drilling the past couple of days it’s noticable that it steers better going in one direction down the field as opposed to coming back up the field.
I have played around with rotating the A/B line on edit AB and as soon as I rotate the line the tractor pulls back onto line. Most strange!
Anybody think of a possible reason for this?

Steering angle sensor not setup accurately enough possibly

Also make sure that there is enough weight on the front steering wheels!