Rotation Flicker in 2d platformer gun

So I've gotten started with Unity recently, and I have been working on a 2d platformer with shooting. Everything is going smoothly but I couldn't help but notice a little flicker whenever I rotate the gun in my game- the rotation works fine but when say the player stops moving right and starts moving left, the rotation flickers for a moment until it goes back to the correct position. I have the gun as a child of the player, and the transform where the bullet comes out as a child of the gun.

Problem can be seen here: https://gyazo.com/0fdb979b2e7e7d8b8448601b5e38fcbb

Script for gun (child of Player):

 public class ShootGun : MonoBehaviour
 {
     public float shotSpread;
     public int pauseRate;
     public Transform bSpawnLocation;
     public GameObject Bullet;
 
     private Vector3 mousePos;
     private Vector3 objectPos;
     private float angle;
     private float rotationAngle;
     private bool mousePressed;
     private GameObject bullet;
     private Rigidbody2D bulletRb;
 
     void Update()
     {
         mousePos = Input.mousePosition;
         mousePos.z = 0;
 
         objectPos = Camera.main.WorldToScreenPoint(transform.position);
         mousePos.x = mousePos.x - objectPos.x;
         mousePos.y = mousePos.y - objectPos.y;
 
         angle = Mathf.Atan2(mousePos.y, mousePos.x) * Mathf.Rad2Deg;
         Debug.Log(angle);
         transform.rotation = Quaternion.Euler(new Vector3(0, 0, angle));
 
         rotationAngle = (transform.eulerAngles.z < 180f) ? transform.eulerAngles.z : 360 - transform.eulerAngles.z;
 
         if (rotationAngle > 90)
         {
             if (transform.localScale.y > 0)
             {
                 transform.localScale = new Vector3(transform.localScale.x, -transform.localScale.y, transform.localScale.z);
             }
         }
         else if (rotationAngle < 90)
         {
             if (transform.localScale.y < 0)
             {
                 transform.localScale = new Vector3(transform.localScale.x, -transform.localScale.y, transform.localScale.z);
             }
         }
 
         if (mousePressed)
         {
             if (Time.frameCount % pauseRate == 0)
             {
                 bullet = Instantiate(Bullet, bSpawnLocation.position, Quaternion.Euler(new Vector3(transform.eulerAngles.x, transform.eulerAngles.y, angle - 90)));
                 bulletRb = bullet.GetComponent<Rigidbody2D>();
                 bulletRb.velocity = new Vector3(Mathf.Cos((angle + Random.Range(-shotSpread, shotSpread)) * Mathf.Deg2Rad) * 20, Mathf.Sin((angle + Random.Range(-shotSpread, shotSpread)) * Mathf.Deg2Rad) * 20, 0);
             }
         }
 
         if (Input.GetMouseButtonDown(0))
         {
             mousePressed = true;
         }
         else if (Input.GetMouseButtonUp(0))
         {
             mousePressed = false;
         }
     }
 }

Main script for Player (should be self explanatory):

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerController : MonoBehaviour
 {
     public float moveSpeed;
     public float jumpForce;
 
     private Rigidbody2D rb;
     private Vector2 velocity;
     private float width;
     private float height;
     private Vector3 scale;
     private Vector3 position;
     private float xScale;
     private bool canJump;
 
     void Start()
     {
         rb = GetComponent<Rigidbody2D>();
         width = GetComponent<Collider2D>().bounds.extents.x * 2.0f;
         height = GetComponent<Collider2D>().bounds.extents.y * 2.0f;
         scale = transform.localScale;
         xScale = scale.x;
     }
 
     void Update()
     {
         position = transform.position;
     }
 
     public void ProcessInput(float horizontal, bool jumpKeyPressed)
     {
         velocity = rb.velocity;
         velocity.x = horizontal * moveSpeed;
         rb.velocity = velocity;
 
         if (jumpKeyPressed && CanJump())
         {
             velocity.y = jumpForce;
             rb.velocity = velocity;
         }
 
         if (velocity.x < 0.0f)
         {
             scale.x = -xScale;
             transform.localScale = scale;
 
             if (transform.GetChild(0).gameObject.transform.localScale.x > 0)
             {
                 transform.GetChild(0).gameObject.transform.localScale = new Vector3(-transform.GetChild(0).gameObject.transform.localScale.x, transform.GetChild(0).gameObject.transform.localScale.y, transform.GetChild(0).gameObject.transform.localScale.z);
             }
         }
         else if (velocity.x > 0.0f)
         {
             scale.x = xScale;
             transform.localScale = scale;
 
             if (transform.GetChild(0).gameObject.transform.localScale.x < 0)
             {
                 transform.GetChild(0).gameObject.transform.localScale = new Vector3(-transform.GetChild(0).gameObject.transform.localScale.x, transform.GetChild(0).gameObject.transform.localScale.y, transform.GetChild(0).gameObject.transform.localScale.z);
             }
         }
     }
 
     private bool CanJump()
     {
         if (Physics2D.BoxCast(transform.position, new Vector2(width, height), 0.0f, Vector2.down, 0.1f))
         {
             return true;
         }
 
         return false;
     }
 }

,