Unexpected behaviour with Combobox in Winform c#

Question

I have this issue when i choose a value from any combobox(DropDownStyle: List) it triggers all the selected index changed to every combobox, that would not be a problem but doing step by step all the combos copy the selected index value that i choosed in the combo box that i made the change.

All the comboboxes has their own SelectedIndexChanged event, for example:

Combo1: Combo1_SelectedIndexChanged, Combo2: Combo2_SelectedIndexChanged, .. etc.

The normal behaviour is to select a value in 1 combobox and fill values in the combobox right next to it, i attach code from selectedindexchanged event in combo 1 and 2 in case is need it.

I already tried to delete all the combos and create them again one by one but it keeps happening, even with only 2 comboboxes in the winform.

Thank you so much for everyone who tried to help.(Also sorry if my english is bad)

/*Combobox1*/ 
   private void comboBox11_SelectedIndexChanged_1(object sender, EventArgs e)
        {
            
                pDataSet = new DataSet();
                pDataSet.Clear();
                pDataSet = neProcesos.NeDataSetCajaCr(13, "", "", "", "", "");

                comboBox111.DataSource = pDataSet.Tables[0];
                comboBox111.DisplayMember = "Description";
                comboBox111.ValueMember = "ID";
                comboBox111.SelectedIndex = 0;

                if (comboBox11.SelectedIndex > 0)
                {
                    pDataSet = new DataSet();
                    pDataSet.Clear();
                    pDataSet = neProcesos.NeDataSetCajaCr(14, comboBox11.SelectedValue.ToString(), "", "", "", "");

                    comboBox111.DataSource = pDataSet.Tables[0];
                    comboBox111.DisplayMember = "Description";
                    comboBox111.ValueMember = "ID";
                    comboBox111.SelectedIndex = 0;
                }
            }
        

/*ComboBox2*/
 private void comboBox12_SelectedIndexChanged(object sender, EventArgs e)
        {
            
                pDataSet = new DataSet();
                pDataSet.Clear();
                pDataSet = neProcesos.NeDataSetCajaCr(13, "", "", "", "", "");

                comboBox121.DataSource = pDataSet.Tables[0];
                comboBox121.DisplayMember = "Description";
                comboBox121.ValueMember = "ID";
                comboBox121.SelectedIndex = 0;

                if (comboBox12.SelectedIndex > 0)
                {
                    pDataSet = new DataSet();
                    pDataSet.Clear();
                    pDataSet = neProcesos.NeDataSetCajaCr(14, comboBox12.SelectedValue.ToString(), "", "", "", "");

                    comboBox121.DataSource = pDataSet.Tables[0];
                    comboBox121.DisplayMember = "Description";
                    comboBox121.ValueMember = "ID";
                    comboBox121.SelectedIndex = 0;
                }
            }
        

Answer 1

The problem was with the source of the data.

Initially it was

  comboBox11.DataSource = pDataSet.Tables[0];
            comboBox11.DisplayMember = "Description";
            comboBox11.ValueMember = "ID";
            comboBox11.SelectedIndex = 0;

            comboBox12.DataSource = pDataSet.Tables[0];
            comboBox12.DisplayMember = "Description";
            comboBox12.ValueMember = "ID";
            comboBox12.SelectedIndex = 0;

then i changed it to their own table from the dataset

  comboBox11.DataSource = pDataSet.Tables[0];
            comboBox11.DisplayMember = "Description";
            comboBox11.ValueMember = "ID";
            comboBox11.SelectedIndex = 0;

            comboBox12.DataSource = pDataSet.Tables[1];
            comboBox12.DisplayMember = "Description";
            comboBox12.ValueMember = "ID";
            comboBox12.SelectedIndex = 0;