Move Foward key W sometimes keeps walking after I let go of W, only happens afew times

Hi Guys,

I am fairly new to Unity, first time posting here.

I have an issue with my W to walk forward. There are usually 3 instances where I will press W, then let go and it will keep moving forward. It happens the very first time I press W, and then after I press W again it will go back to my idle/standing animation. After this first issue, it then works normally where it walks when I press W, and stops when I let go of W. It will then proceed to happen 1 or 2 more times at random after some more successful walking attempts.

I have pasted in my full script. I have been following this guide: https://www.youtube.com/watch?v=ReauId6jFFI

Thanks in advance :)

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerController : MonoBehaviour
 {
     float speed = 4;
     float rotSpeed = 80;
     float rot = 0f;
     float gravity = 8;
 
     Vector3 moveDir = Vector3.zero;
 
     CharacterController controller;
     Animator anim;
 
     void Start()
     {
         controller = GetComponent<CharacterController>();
         anim = GetComponent<Animator>();
     }
 
     void Update()
     {
         Movement();
         GetInput();
     }
 
     void Movement()
     {
         if (controller.isGrounded)
         {
             if (Input.GetKey(KeyCode.W))
             {
                 if (anim.GetBool("attacking") == true)
                 {
                     return;
                 }
                 else if (anim.GetBool("attacking") == false)
                 {
                     anim.SetBool("walk", true);
                     anim.SetInteger("condition", 1);
                     moveDir = new Vector3(0, 0, 1);
                     moveDir *= speed;
                     moveDir = transform.TransformDirection(moveDir);
                 }
             }
             if (Input.GetKeyUp(KeyCode.W))
             {
                 anim.SetBool("walk", false);
                 anim.SetInteger("condition", 0);
                 moveDir = new Vector3(0, 0, 0);
             }
         }
         rot += Input.GetAxis("Horizontal") * rotSpeed * Time.deltaTime;
         transform.eulerAngles = new Vector3(0, rot, 0);
 
         moveDir.y -= gravity * Time.deltaTime;
         controller.Move(moveDir * Time.deltaTime);
     }
 
     void GetInput()
     {
         if (controller.isGrounded)
         {
             if (Input.GetMouseButtonDown(0))
             {
                 if (anim.GetBool("walk") == true)
                 {
                     anim.SetBool("walk", false);
                     anim.SetInteger("condition", 0);
                 }
                 if (anim.GetBool("walk") == false)
                 {
                     Attacking();
                 }
             }
         }
     }
 
     void Attacking()
     {
         StartCoroutine(AttackRoutine());
     }
 
     IEnumerator AttackRoutine()
     {
         anim.SetBool("attacking", true);
         anim.SetInteger("condition", 2);
         yield return new WaitForSeconds(0.800F);
         anim.SetInteger("condition", 0);
         anim.SetBool("attacking", false);
     }
 }