Helper Collsions problem, setting them up

[Josewilliams]

So i have been setting up Helper collisions.
collisionMask="20"

But the Helper is failing to see the collisions to the point it drives straight through them (hence hit the hedge/tree), however if a i use a large tractor e.g. T7, it works always.
With smaller machines is does not work, I've tried a new game. Tried freezing scale and rotation.
The Fendt 300 and the small Valtra both have this problem.

If i run these tractors without a weight or front seed tank they will see the col, but with them they don't.
The hedges are about 2 meters off the edge of the field.
This happen with standard trees even when 5 meters away.
This is very annoying as i can't use the new Kuhn 3point seeder with the Helper as i need the tank on the front.

Help would be most appreciated as this is driving me up the wall.

Thanks

[Josewilliams]

Little more info, all the kuhn seeders seem to cause the same issue with the Helper ignoring collisions.
If i use the little knerverland seeder, i get no issue, same with ploughs, 3m cultivators, 4m power harrows even fert spinners.
I will have to test more but the issue seems to relate to tractors under 200hp.