Weird annimation bug when loading level

Hello, when I load my level trough unity it self, the animation made by this script go crazy Here's the script:

 void Update () {
         gameObject.transform.Rotate(Vector2.up * 5 / 2);
     }

it simply rotates the game object normally, but when I load the level through script like a button that make "Application.LoadLevel("X");" it "detach" the model's form and rotate around. Here's a screenshot to help visualize:

And here's the hierarchy when I load it through Unity(Left) and through code(Right)

There's really nothing wrong at my point of view I check my code, everything that can possibly influence this bug, but nothing... Thanks for giving it a try !