[ASSETS] [OPEN SOURCE] Tanks, tracks and N-wheeled vehicles

I’ve been testing with an excavator setup.

I removed the idler and sprocket and use only the roadwheels here.

but I noticed some weird collision behaviour.

Whenever any colossion volume comes over another (hope I’m explaining it right)… it stops the excavator from being able to move foreward.

I hope it’s visible in the video… The cabin and all the rest is a child object of the hull.
The bucket and the arm have a collision object.

Whenever one of these inline with the Z axis go “over” something on the floor… it stops the excavator.
When I remove the collision from the bucket and arms… all is fine.

There is no direct collision (the arm is raised high enough to clear everything) , It looks as If everything in the hierarchy upwards of the hull get’s checked in the Z direction down to the ground.

Any thoughts on this?