My prefabs always spawn twice at different positions

Questions & Answers
1

So I’m working on a game where I want to randomly spawn different arrangements of blocks as obstacles.
I created an empty gameobject as a parent and put the blocks around it as children so I adjust the position properly. Afterwards I created a prefab of this and loaded it into an array so I can randomly choose one in the future. But if I now want to spawn the prefab with a custom position it not only spawns there but also on the position the prefab itself has assigned to. Is there a way to prevent this?
My code:

void Start()
    {
        prefab[0] = GameObject.Instantiate(Resources.Load("prefab1")) as GameObject;
        // Instantiate at position (0, 0, 0) and zero rotation.
        Instantiate(prefab[0], new Vector3(0, 1, 140), Quaternion.identity);
        Instantiate(prefab[0], new Vector3(0, 1, 120), Quaternion.identity);

    }

Interestingly I can initiate two objects of the same type but the bug only occurs once.

2

I just noticed that my declaration to the array contained an initiation command. My question is now if I could put the gameobject into the array without spawning it rightaway.

My current code (only spawns at start tho):

void Start()
    {
        prefab[0] = GameObject.Instantiate(Resources.Load("prefab1"), new Vector3(0, 1, 140), Quaternion.identity) as GameObject;

    }