It is tied to [data-request] and does not work when using $.request.

"Workaround" it to the stuff by yourself:

$.oc.stripeLoadIndicator.show()

$.request('onButtonClick', {
    data: {val: props.value},
    success: props.onNewResult,
    complete: () => $.oc.stripeLoadIndicator.hide(),
})

You can use "loading" attribute:

$.request('onLoadFLipbook', {
            loading: $.oc.stripeLoadIndicator,
            success: function (data) {
                $('#flipbook').html(data.partial);
                const book = document.getElementById('book');
                const module = prepareFlipbook(data.aspectWidth, data.aspectHeight);
                module.init('book');
            }
        });