Hey Marcel –
When I deactivate the plugin, the 404 page does present on the woocommerce pages, which are currently redirected using your plugin, but I still have the same issue if say, I go to the ysurfaceshop.wpengine.com/xyz, which is a page that doesn’t exist.
Not sure if that answers your question!
Is there a setting in your plugin which would ordinarily redirect any/all mistyped urls to the home page automatically?