there is bug in my file located at https://pasteall.org/blend/960d180f237343f3a2e8a9af8f767f42 where the cube is not properly touching the surface of the rigid "passive" curvy flooring. I used shape "Mesh" for the curvy flooring and for the cube i tried using shape box, convex hull, mesh but nothing works. The cube is levitating above the ground. Is this a blender bug?
looks like the curve is causing a problem, it repositions, offsets the flooring, but the objects collision points do not move along with the flooring, it can be tested by going into edit mode for the floor, notice how the flooring shifts. i think it's a bit counter intuitive if the collision points don't move along.