Collision understand

There is something of mysterious in collision channel that i not understand.
I do not want to enemies collide among them, well, i set to preset no collision and ignore pawn, then the first 2 enemies who use this setting working right, they don’t collide.
But the third enemy(and third actor) that have the same exactly setting ( copy paste the class, can’t be different) same parameters, same channel collide and same setting, it doesn’t work. He’s collide with other enemy as i have setted capsule or mesh block but is strange, it’s setted ignore.
Someone understand this?
Why same setting but different behaviour?