Object resets position on first movement.

I have plane model exported form 3ds, translated in blender.

I attached TTP camera to it as child in hierarchy, and my script attached to plane:

 public class PlaneMoveController : MonoBehaviour {
     public float speed = 10.0f;
     
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () {
         //move plane forward
         transform.position += transform.forward.normalized * speed * Time.deltaTime;
     }
 }

Starting position of my plane is {100, 50, 100} rotation {0,0,0}. When I start game plane's position changes to {0,0,0} rotation to {270,0,0} My scene has 3 objects plane, camera, terrain.

Have you any ideas how to fix it?