Duplication(instance) re-create deleted children

Hello,

I'm kinda stucked :|

I'm trying to duplicate a group with children, with varying number of children in them. When I instantiate it, deleted children of the duplicated group reappears on the duplicated group.

For example; I want to duplicate this : Cubes being randomly deleted on this specific pattern_1

But when it's instantiated I got this :

As it was duplicating the prefab used instead of the gameObject, which is odd, because in my code I have this line :

 currentInstance.transform.parent = GameObject.Find("pattern_1");

Which define the whole object to duplicate, the group, and which come at the very end of every steps of generating the ground & deleting Cubes.

Anyone has ever had the same issue and -hopefully- found a solution ? I'm stuck on this ... thanks.

Arthur