I have an application at localhost:8080 that receives every request and rewrites to the correct app. This application is called router.
In the image, you can see the router receives the request, and rewrites to the correct app depending on the path. (for example, localhost:3001/login)

When rewriting to an application using that is still using pages folder, the router app "throws" Fast Refresh had to perform a full reload. in a loop.
When rewriting to an application using app folder, the problem disappears.

Every app is using NextJS v14.04 but some apps are still using pages folder and others are using the new app folder.
This only happens in apps using pages folder