Transform values reseting after Start() call

I'm seeing bizarre behavior when I instantiate an object. I can set values in Awake or Start, but they are reset immediately after Start is done. Observe:

Code (csharp):

1.  
2. public class RacePlayer : MonoBehaviour {
3.     public TubeRacer carPrefab;
4.     private GameObject carHandle;
5.     private TubeRacer car;
6.    
7.     public void Start()
8.     {
9.         carHandle = new GameObject("Race Handle");
10.         car = (TubeRacer)GameObject.Instantiate(carPrefab,Vector3.zero,Quaternion.identity);
11.         car.transform.parent=carHandle.transform;
12.         car.transform.localPosition = new Vector3(0,-5f,0);
13.         Debug.Log(car.transform.localPosition.y);
14.         StartCoroutine(Report());
15.     }
16.    
17.     IEnumerator Report()
18.     {
19.         yield return 0;
20.         Debug.Log(car.transform.localPosition.y);
21.         yield return 0;
22.     }
23. }
24.  

This script is the only object in the scene (and TubeRacer is an empty C# class that extends MonoBehavior), but this is my debug output:

-5
0

and, indeed, the localPosition of the child object is 0's across the board.

Why is this being reset? I have recompiled the project twice and built it from script up, and I'm still seeing this. I'm new to C#, but I know you can't set the .x, .y and .z parts of its localPosition manually... is something similar to that happening? Why does the Debug output work?


Update: recompiling a third time fixed it. Odd.