Null reference on invalid culture

[ziraak]

was trying out the sdk with this test case:

var b = new SdkClient(() => new ConsoleLogger());

var request = b.CreateRequest().Authenticate(key, secret, false, culture: System.Globalization.CultureInfo.CurrentCulture)
    .TransactionRequest()
    .SetBasicFields(new BuckarooSdk.DataTypes.RequestBases.TransactionBase()
    {
        AmountDebit = 10,
        Currency = "EUR",
        Invoice = "testinvoice 123",
        ReturnUrl = "http://wwww.google.com"
    });

ConfiguredServiceTransaction? transaction = paymentMethod switch
{
    ServiceNames.Sofort => request.Sofort().Pay(request: new BuckarooSdk.Services.Sofort.SofortPayRequest()),
    ServiceNames.Ideal => request.Ideal().Pay(new BuckarooSdk.Services.Ideal.TransactionRequest.IdealPayRequest()),
    ServiceNames.PayPal => request.PayPal().Pay(new BuckarooSdk.Services.PayPal.PayPalPayRequest() { ProductName = "name", BillingAgreementDescription = "", BuyerEmail = "", PageStyle = "" }),
    _ => throw new Exception(""),
};

var response = transaction?.Execute();

this returned for me a 400: Culture header could not be parsed. The provided value is not a known culture.
but the sdk does not give that response. instead it will give a null reference exception on line 47 of ConfiguredServiceTransaction.