A new feature is added today. For users who go to a page where it doesn't exist in the forum, they will now to be redirected to the root path of your forum.
However, you can specify which page the redirection occurs and can redirect them to a custom page that you create in Shopify.
How to create a custom page: https://help.shopify.com/en/manual/sell-online/online-store/pages
To change this setting, go to Settings in the Champ and scroll to the 404 Redirection section:
