Object falling through terrain with script

Hi! First i want to sorry for my english, it's not my native language.

I have this little script that resizes object ( the player ) from 1.0 to 0.5 on the axis Y.

 using UnityEngine;
 using System.Collections;
 
 public class Dodge : MonoBehaviour {
 
     public bool isDodged = false;
     // Use this for initialization
     void Start () {
           isDodged = false;
     }
     
     // Update is called once per frame
     void Update () {
          if    ( Input.GetKeyDown(KeyCode.LeftControl)) isDodged = true;
             if ( isDodged == true ) {
             
                Vector3 scale = transform.localScale;
                scale.y = 0.5f; // This is where it decreases to 0.5
                transform.localScale = scale;
         }
         
          if    ( Input.GetKeyUp (KeyCode.LeftControl)) isDodged = false;
             if ( isDodged == false ) {
             
                Vector3 originalsize = transform.localScale;
                originalsize.y = 1f;
                transform.localScale = originalsize;
         }
     }
 }

I start with original 1.0 value, when i hold down LeftCTRL the player decreases to 0.5, and after i release the button, it goes back to 1.0 Yes, this works, but when it goes back to size 1.0, it falls through the map. I think its because it doesn't has time to calculate colission with map, OR it begins to resize from the center, so a little part remains under the terrain. How could i fix that?

Thank you!