Help me with my ai controller

Hello, i'm working on a game and i get this weird behaviour :

here is my code :

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class OuvrierController : MonoBehaviour
 {
     private GameObject marmottes;
     private bool wandering = true;
 
     void Start()
     {
         marmottes = GameObject.Find("Marmottes");
     }
 
     // Update is called once per frame
     void Update()
     {
         if(wandering) {
             WanderAround();
         }
     }
 
     void WanderAround() {
             Collider[] hitColliders = Physics.OverlapSphere(transform.position, 1);
             List<GameObject> outcomes = new List<GameObject>();
 
             foreach (var hitCollider in hitColliders)
             {
                 if(hitCollider.gameObject.name == "groundTile") {
                     outcomes.Add(hitCollider.gameObject);
                 }
             }
 
             int targetID = (int)(Random.value*outcomes.Count);
 
             Vector3 target = outcomes[targetID].transform.position;
             transform.position = target;
 
             outcomes.Clear();
     }
 }

When doing this the character moves randomly at insane speed but it's normal. The problem is that the character is IN the groundTile, so i tried to set the y to 1.5 (the height i needed) with a huge lot of different ways, but everytime the character stops to move. Do anyone have an idea why ?