Parameter Missing or Invalid: Required parameter missing or invalid: channel

We have a homepage where we integrate shopify using @shopify/buy-button-js this worked well until lately.

Out of the blue (no code or config change) we got the following error if a user tried to checkout:
Parameter Missing or Invalid: Required parameter missing or invalid: channel

The URL where the checkout redirected the user and where the error appeared was:
https://shop.myDomain.xx/cart/c/hWN3GVUNI6d0pgq3QFiiAnyA?key=someKey&channel=buy_button

I saw that the cause was in @shopify/buy-button-js/dist/buybutton.js:15038

  /**
   * get params for online store URL.
   * @return {Object}
   */

}, {
  key: "onlineStoreParams",
  get: function get() {
    return {
      channel: '**buy_button**',
      referrer: encodeURIComponent(windowUtils.location()),
      variant: this.selectedVariant.id.split('/')[4]
    };
  }

I noticed that the checkout worked in case I completely removed the channel. (https://shop.myDomain.xx/cart/c/hWN3GVUNI6d0pgq3QFiiAnyA?key=someKey)

I go this to work with the

.createComponent('cart', {
 options: {
      "cart":  events: {
      beforeInit: (chart) => {
 cart.checkout.open = function(url: string): void {
    // open it in a new tab
    windowReference = window.open();
    windowReference!.location = url.replace('&channel=buy_button', '');
  }
},
    },

This workaround works but I would like to know how it come to that issue and my fix seams to be really dirty so what do I need to do to fix this properly?

Any input is appreciated.

Start by reproducing the checkout redirect and inspect @shopify/buy-button-js/dist/buybutton.js:15038, especially the onlineStoreParams channel value. Compare checkout behavior with and without channel=buy_button; done means identifying a supported fix so checkout works without the caller's URL-replacement workaround.