Unexpected_Error 500 when modifying app data via patch method

I am trying to modify my app fields via the appstoreconnect api call here: https://developer.apple.com/documentation/appstoreconnectapi/modify_an_app_info
However, I'm getting the following error whenever I try the api call:
{
    "errors": [
        {
            "status": "500",
            "code": "UNEXPECTED_ERROR",
            "title": "An unexpected error occurred.",
            "detail": "An unexpected error occurred on the server side. If this issue continues, contact us at ***
        }
    ]
}

I am using the URL https://api.appstoreconnect.apple.com/v1/apps/id_here with the following headers using Postman:
    headers = {
    'Content-Type': "application/json",
    'Authorization': "Bearer "+token.decode("utf-8"),
    'User-Agent': "PostmanRuntime/7.11.0",
    'Accept': "*/*",
    'Cache-Control': "no-cache",
    'Postman-Token': "***",
    'Host': "api.appstoreconnect.apple.com",
    'accept-encoding': "gzip, deflate",
    'Connection': "keep-alive",
    'cache-control': "no-cache"
    }

and my JSON body is as follows:
{
    "data": {
        "type" : "apps",
        "id" : "xxxx",
        "attributes" : {
            "availableInNewTerritories": true
        },
        "relationships": {
            "availableTerritories" : {
                "data": [
                    {
                    "type": "territories",
                    "id": "***"
                    }
                ]
            }
        }
    }
}
Other api calls work completely fine. I am able to get, post, and even patch my appInfos fields as detailed here: https://developer.apple.com/documentation/appstoreconnectapi/modify_an_app_info
I am only seeing this issue with this one specific call. Any advice/suggestions?