How to change the collin hf an undamed destrucible?

I have a simple scene with a big bridge(destructible), I also have set the collision complexity to “use complex collision as simple”.
If I place the mesh (not destructible) I can move around without any strange things but if I generate a destructinel mesh from this and try to do the same, there are invisible walls like a simple collision mesh until I damage the destructible.

Do anyone know how to fix that ?