If you are referring to the arcane vault clipping into a unit, then you will need to either shrink the arcane vault model scale or increase the arcane fault pathing footprint size. The problem currently is that the arcane vault model extends beyond its pathing footprint so that units can walk inside the model's corners.
If the arcane vault cannot use a pathing footprint, such as because it is not classed as a building, then you will need to either increase the unit collision radius or decrease the model scale. Due to technical limits on how large unit collision radius can be made, you might have to resort to shrinking the model scale