Parts of code not running on instances, weird

Hi, i'm having a problem with some instantiated prefabs or maybe i'm missing something in the way instances work.

I'm having a lot of problems trying to get to run some specific lines of code in the various instances but I found one thing that really puzzles me and maybe someone can point me in the right direction.

Weird Stuff #1: I have 5 instances of a prefab created with a "for" loop, this prefab has a script with some code on Update().

 if(this.transform.position.z < -40){
            this.transform.Translate(0,0,200);
            Debug.Log("I'm moving");
        }

The instances are moving as they should by another external script and the transformation in this code is being done but the Log is only running once, ever.

Weird Stuff #2:then there's this code I used to generate the instances:

 function NuevoCamino (){
     
     for(var i = 0; i < 5; i++){
         var position = Vector3(0,-i,40*i);
         trayecto.Push(Instantiate(caminoPrefab, position, Quaternion.identity));
         Debug.Log("instancing..."); //HERE'S WHATS WRONG!!!
     }    
 }

If the last line is like that it traces "instancing..." only once but if I change it to: Debug.Log("instancing..."+i) it traces instancing...0 instancing...1 instancing...2 instancing...3 instancing...4

It's not happening only with the Debug.Log() lines, it's happening with a lot more code but this is the easier to track down. So, i'm out of ideas here, any guidance will be welcome. thanks