Why is my Remix app's data fetch request getting cancelled?

Small update → I’ve recreated a remix project with a similar layout with a base route that holds a nav with s and an for routing. The reproduction is using the same server as I’m trying to get working within the Shopify app. Both frontend and backend are served up over https via ngrok with the same auth mechanism in place on the backend. This works without issue outside of the Shopify ecosystem. What could be different with this as an embedded app in Shopify? I haven’t seen a lot of examples of a separate backend for the domain logic, but I’m assuming at least some other people must have this setup?