Index was outside the bounds of the array. While Clearly it wasn't(unity)

IndexOutOfRangeException: Index was outside the bounds of the array. RowManager.GenerateRow (System.Single hbias, System.Single vbias) (at Assets/Scripts/RowManager.cs:155) GameManager.Update () (at Assets/Scripts/GameManager.cs:38) The array has five cells and I index it from 0 to 4. Unity 2021.3.8f LTS

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
class Baze
{
    private byte Start,End;
    public Baze()
    {
        Start = 0;
        End= 0;
    }
    public void SetStart(byte s)
    {
        Start = s;
    }
    public void SetEnd(byte s)
    {
        End = s;
    }
    public byte GetStart()
    {
        return Start;
    }
    public byte GetEnd()
    {
        return End;
    }
    public void Correction()
    {
        if(Start>End)
        {
            byte temp = Start;
            Start = End;
            End = temp;
        }
    }
    public bool isSingular()
    {
        return Start == End;
    }
}
class MazeLogic
{
    private List<SortedSet<byte>> Groups;
    private SortedSet<byte> TempSet;
    private Baze TempRange;
    private List<Baze> Template;
    private uint[] IDs;
    private bool[] Hjoints, Vjoints;
    public MazeLogic()
    {
        Groups = new List<SortedSet<byte>>();
        TempRange = new Baze();
        IDs = new uint[5] {1,2,3,4,5};
        Hjoints = new bool[5] {false,false,false,false,false};
        Vjoints = new bool[5] {true,true,true,true,true};
        TempSet = new SortedSet<byte>();
        Template = new List<Baze>();
        for(byte i=0;i<4;i++)
        {
            TempRange.SetStart(i);
            TempRange.SetEnd((byte)(i + 1));
            Template.Add(TempRange);
        }
    }
    private void SetGroups(float bias)
    {
        uint temp = 0;
        for(byte i=0;i<5;i++)
        {
            Hjoints[i]= false;
            if (Vjoints[i])
                temp = IDs[i];
            else
                IDs[i] = 0;
        }
        for (byte i = 0; i < 5; i++)
            if (IDs[i] == 0)
                IDs[i] = ++temp;
        TempRange.SetStart(0);
        for(byte i=0;i<4;i++)
        {
            if (Random.value > bias && IDs[Template[i].GetStart()] != IDs[Template[i].GetEnd()])
            {
                TempSet.Add(Template[i].GetStart());
                TempSet.Add(Template[i].GetEnd());
            }
            else
            {
                TempSet.Add(Template[i].GetStart());
                Groups.Add(TempSet);
                TempSet.Clear();
            }
        }
        for (byte i = 0; i < Groups.Count; i++)
            for (byte j = Groups[i].Min; j < Groups[i].Max; j++)
                Hjoints[j] = true;
    }
    private void SetVjoints(float bias)
    {
        bool check;
        for (byte i = 0; i < Groups.Count; i++)
        {
            check = false;
            for (byte j = Groups[i].Min; j <= Groups[i].Max; j++)
                if(Random.value>bias)
                {
                    check = true;
                    Vjoints[j] = true;
                }
            if (!check)
                Vjoints[Random.Range(Groups[i].Min, Groups[i].Max + 1)] = true;
        }
    }
    public void GenerateMaze(float hbias,float vbias)
    {
        SetGroups(hbias);
        SetVjoints(vbias);
    }
    public bool[] GetHorizontalJoints()
    {
        return Hjoints;
    }
    public bool[] GetVerticalJoints()
    {
        return Vjoints;
    }
}
public class RowManager : MonoBehaviour
{
    [SerializeField] GameObject[] Hwalls;
    [SerializeField] GameObject[] Vwalls;
    MazeLogic ml;
    void Awake()
    {
        ml = new MazeLogic();
    }
    void Start()
    {
        Hwalls = new GameObject[4];
        Vwalls = new GameObject[5];
        for (byte i = 0; i < 4; i++)
            Hwalls[i] = transform.GetChild(i).gameObject;
        for (byte i = 0; i < 5; i++)
            Vwalls[i] = transform.GetChild((byte)(i+4)).gameObject;
    }
    public void GenerateRow(float hbias,float vbias)
    {
        ml.GenerateMaze(hbias,vbias);
        for (byte i = 0; i < 4; i++)
            if (ml.GetHorizontalJoints()[i])
                Hwalls[i].SetActive(false);
        for(byte i=0;i<5;i++)
            if (ml.GetVerticalJoints()[i])
                Vwalls[i].SetActive(false);//line 155
    }
    public void Reset()
    {
        for (byte i = 0; i < 4; i++)
                Hwalls[i].SetActive(true);
        for (byte i = 0; i < 5; i++)
                Vwalls[i].SetActive(true);
    }
}

and array is also not null enter image description here