"stretching" of an object Instantiated from prefab

Questions & Answers
1

I am trying to spawn obstacles on the road. To do so, I generate a road by spawning its parts, and each part itself spawns several obstacles in bounds of themselves. But some prefabs after being instantiated got strange “stretching” effects. I don’t know how to explain it, so I recorded a small video 1.
Also, if I spawn that same object by “drag n drop” to the scene, this bug never appears.

This how I spawn obstacles:

            Vector3 size = GetComponent<Renderer>().bounds.size;
            Vector3 pos = new Vector3(Random.Range(-0.3f*size.x,0.3f*size.x), 30, Random.Range(-0.3f*size.z,0.3f*size.z));
            Debug.Log(pos + transform.position +"");

            GameObject newBottle = Instantiate(minus_prefabs[Random.Range(0, minus_prefabs.Length)], new Vector3(transform.position.x+pos.x,transform.position.y + pos.y,transform.position.z+pos.z), Quaternion.Euler(0, 0, 0));
            newBottle.transform.SetParent(transform);
2

Given the videos information i assume that the Problem you are facing here is that the parent of the object does not have a scale of (1, 1, 1).
You should try to avoid this at all cost.if you have visuals that have to be stretched put them on their own transform without any children to avoid this issue.