For some reason my code is spawning in my zombies when it is not supposed to and I don't know why

Questions & Answers
1

This script is supposed to spawn in my zombies in waves. My problem is that it spawns in the second wave when it isn’t supposed to and I don’t know why this is doing this. I know that enemyCount isn’t 0 because when the game ran I checked and confirmed that it is over 0. Is it possible for someone to have a look at the code and tell me whats wrong. I haven’t been able to find anything. Thanks!

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Waves : Zombie
{
    public int enemyCount;
    public GameObject behemoth;
    public GameObject runner;
    public GameObject zombie;
    private int xPos;
    private bool HasSecondWaveRan;
    private bool HasThirdWaveRan;
    public int enemyCount2 = 1;


    // Start is called before the first frame update
    void Start()
    {
        for (int i = 0; i < 10; i++)
        {
            xPos = Random.Range(31, -14);            
            Instantiate(zombie, new Vector3(xPos, 0.4f, 6), Quaternion.identity);
            enemyCount = enemyCount + 1;
        }

        for (int i = 0; i < 3; i++)
        {
            xPos = Random.Range(31, -14);            
            Instantiate(runner, new Vector3(xPos, 0.4f, 6), Quaternion.identity);
            enemyCount = enemyCount + 1;
        }

    }

    // Update is called once per frame
    void Update()
    {
        if (enemyCount == 0)
        {
            StartCoroutine(SecondWave());
            HasSecondWaveRan = true;
        }        
        
        if (enemyCount2 == 0)
        {
            StartCoroutine(ThirdWave());
            HasThirdWaveRan = true;
        }
    }

    IEnumerator SecondWave()
    {
        if (HasSecondWaveRan == false)
        {
            yield return new WaitForSeconds(5.0f);

            for (int i = 0; i < 5; i++)
            {
                xPos = Random.Range(31, -14);
                Instantiate(runner, new Vector3(xPos, 0.4f, 6), Quaternion.identity);
            }

            for (int i = 0; i < 20; i++)
            {
                xPos = Random.Range(31, -14);
                Instantiate(zombie, new Vector3(xPos, 0.4f, 6), Quaternion.identity);
            }

            enemyCount2 = 25;
            enemyCount = 1;
            HasSecondWaveRan = true;
        }
    }

    IEnumerator ThirdWave()
    {
        if (HasThirdWaveRan == false)
        {
            yield return new WaitForSeconds(5.0f);

            for (int i = 0; i < 5; i++)
            {
                xPos = Random.Range(31, -14);
                Instantiate(runner, new Vector3(xPos, 0.4f, 6), Quaternion.identity);
            }

            for (int i = 0; i < 20; i++)
            {
                xPos = Random.Range(31, -14);
                Instantiate(zombie, new Vector3(xPos, 0.4f, 6), Quaternion.identity);
            }
            
            HasThirdWaveRan = true;
        }
    }
    
}
2

I fixed it by preseting enemyCount to 1. I can assume that the problem was that the update somehow happened before the enemyCount updated(lag)