Rigidbody below terrain getting dragged

If a rigidbody is below a terrain it is getting dragged up on the terrain

I have 2 terrains, one over another to make a cave like shape. If I put a rigidbody on terrain below it is getting dragged onto the terrain above. So i cant even put a single rigidbody inside that cave.

I tried with mesh collider on terrain obove instead of using terrain collider. But terrain does not have an actual mesh, so it didnt work.

Is there a solution to overcome this?

Hi you could try this and then put the mesh collider onto it