Modal `onlineStore` for `buttonDestination` is causing 404 redirect

Problem

Buy Button Modal onlineStore is not working as intended. The modal does not redirect the customers to the product page.

Impact

Referencing online public document: https://github.com/Shopify/buy-button-js/blob/master/docs/customization/index.md

There's roughly 18 - 22 tickets that were open and closed on this combined.

Examples

Example test shop redirect link: https://workout-with-eddy.myshopify.com/null?channel=buy_button&referrer=https%3A%2F%2Fworkout-with-eddy.myshopify.com%2F&variant=32274934541&

Admin Internal

Merchant admin Marchant internal

Where merchant buy buttons are located ( currently merchant is using a call to action button instead)

Code being used:

buttonDestination
'cart' Adds product to cart and opens cart
'modal' Opens a modal window with further details about the product
'checkout' Opens a pop-up window directly to checkout
'onlineStore' Open product in your online store (Note: requires Online Store channel be active and product be visible in Online Store)
Type: String: 'cart', 'modal', 'checkout', 'onlineStore'
Default value: 'cart'

Source: https://github.com/Shopify/buy-button-js/blob/master/docs/customization/index.md Keep getting a 404.

Expected Vs Actual

What did you expect to happen, and what actually happened? Use screenshots or a screencast.

Expected: Using the modal onlineStore should redirect the user to the product page of that product in their online store.
Actual: Using the modal onlineStore should redirect the user to the product page of that product in their online store but instead they are getting a 404 error.

Replication Steps

Create a Buy button product
Go to the Buy Button code and edit the buttonDestination value to onlineStore
save it with the new change
Go to online page where the button

The redirect will go to a 404 page instead of the product page.

More Information

Closed long ago issue: https://github.com/Shopify/buy-button-js/issues/403 https://github.com/Shopify/buy-button-js/issues/486

Zendesk Ticket

Shopify / buy-button-js

Modal `onlineStore` for `buttonDestination` is causing 404 redirect #782