Plane splitting issue

[rebirth123]

If I have a cube that has a uniform scale of 1.0 and perform a union with a smaller cube that only intersects with one plane (side) of the first cube, the opposite side of the first cube also ends up with added vertices despite having no intersection. Is there a way to restrain the algorithm to the plane or planes that intersect?

The splits seem OK on the faces that required splitting, so I feel the algorithm could be improved instead of adding any post functions to reduce excessive vertices on a plane.