Access to loan balance from API

I’m trying to access the balance on my loan account, I call the /accounts endpoint like normal, get a total of 4 accounts: current account, flex account, old loan, and current loan.

Retrieving the balance of the current account & flex account works fine, but when I try to get the balance of the loans I just get the 200OK response of:

{
    "balance": 0,
    "total_balance": 0,
    "balance_including_flexible_savings": 0,
    "currency": "GBP",
    "spend_today": 0,
    "local_currency": "",
    "local_exchange_rate": 0,
    "local_spend": []
}

I can’t find anything on the docs or other posts that suggest retrieving the balance of loans is done any different, am I missing something or is the API just not working correctly for loans?