Ok I fix the first bug by instantiate a new RigidBodyControl for each chunk refresh.
If I don’t do that and only “setCollisionShape(newMeshShape)”, in some cases the collisions have strange effects.
The graphics was not disappearing but somehow the camera location was set to Vector3f.NAN
But my character still get stuck in or get trough the ground when he hit it with a high velocity. Any ideas why? Is this normal?