PayPal Checkout console error: Cannot query field "supplementary" on type "Cart"

I implemented PayPal with PayPal buttons. Everything worked smoothly till today. For a few hours now I'm getting the following error:

Error: Cannot query field "supplementary" on type "Cart".

I don't use such a field and no cart within my implementation. Did anyone of you experience the same? Checkout not possible.

This is my code:

    paypal.Buttons({
    env: paypalEnvironment,
    locale: language + '_' + country,
    style: {
        layout:  'vertical',
        color:   'silver',
        shape:   'rect',
        label:   'paypal'
    },
    createOrder: function(data, actions) {
        return actions.order.create({
            purchase_units: [{
                amount: {
                    value: value,
                    currency_code: currency
                }
            }],
            application_context: {
                shipping_preference: 'NO_SHIPPING'
            }
        });
    },
    onApprove: function (data, actions) {
        ...
    },
    onCancel: function (data) {
        showError ();

        console.log (data);
    },
    onError: function (data) {
        showError (data);

        console.log (data);
    }
}).render('#paypal-button-container');