How to block sphere penetrating the terrain

Recently, i am developing a game to roll the sphere on the indented terrain and i found that the rolling sphere sometimes penetrating the terrain and then popup on the terrain.

i changed mass value of sphere and set triggers on colliders but didn’t work at all.

Someone said it might be due to sphere’s speed. it’s too fast and goes through terrain before it’s updated.
but sphere is not that fast. can someone give me any solutions or advice ?

Maybe collisionDetectionMode is helpful Unity - Scripting API: Rigidbody.collisionDetectionMode
Unity - Scripting API: CollisionDetectionMode.ContinuousDynamic

Change the Collision Detection property of attached rigid body to Continuous 90299-rb.png