Physical mesh projectile and destructible issues

Hello, i’m having trouble understanding something about DM.

I need a projectile that is physically calculated (used for other features in the game), and i want it to break large windows made of glass.
So i use the following settings :

The “FPS Template” projectile.
Projectile’s Collision Component settings :

A large window in BSP turned into a Mesh, turned into a Destructible Mesh.
DM settings :

My problem is that i can make a hole in the DM in the first shot, but then the DM become unbreakable and seem to not react to my other projectiles.

1 : Do you know if it’s a bug or just my bad on the settings ?

2 : Is there a way to NOT apply damage to a DM despite the fact that “simulate physics” is marked on the projectile. So i could use a radial damage on hit to break the DM.

Thanks for your time!

-Edge