Buttons in one panel affecting another.

I have 2 panels, which are being dynamically filled with buttons. The first is filled like this:

     public GameObject m_button;
     public ItemPanelButtons itemPanelButtons;
 
     // Use this for initialization
     void Start ()
     {
         foreach(var type in System.Enum.GetValues(typeof(InventoryItemType)))
         {
             GameObject button = (GameObject)Instantiate(m_button, Vector3.zero, Quaternion.identity);
             button.transform.SetParent(transform, false);
             string typeStr = type.ToString();
             //Add space before each uppercase letter
             string output = System.Text.RegularExpressions.Regex.Replace(typeStr, "([a-z])_?([A-Z])", "$1 $2");
             button.transform.FindChild("Text").GetComponent<Text>().text = output;
             button.GetComponent<Button>().onClick.AddListener(() => itemPanelButtons.AddItemButtons(typeStr));
         }
     }

The second is filled when the using the itemPanelButtons.AddItemButtons() function.

 public InventoryManager inventory;
 public GameObject m_button;
 public RectTransform itemPanel;

 public void AddItemButtons(string type)
 {
     for(int i = 0; i < inventory.inventory.Count; i++)
     {
         if(inventory.inventory[i].m_category.ToString() == type)
         {
             GameObject button = (GameObject)Instantiate(m_button);
             button.transform.SetParent(itemPanel, false);
             button.transform.FindChild("Text").GetComponent<Text>().text = inventory.inventory[i].m_name;
         }
     }
 }

When type button is pressed, and the inventory array is empty or there is nothing of that type in the inventory, as expected. However, if a button is added to the item panel, or even if I start the game with a button already in the item panel, the buttons in the type panel become disabled. They do not show the disabled color, but clicking them has no effect. I can even print a string using them.

The entire project can be accessed from here: https://www.dropbox.com/sh/egx4nft9o6hkmnd/AAAKL-CKGOGnpSPL3RwQol8ga?dl=0.

Thank you in advance.