Editor forces window reload

The first time that the editor is loaded it's forcing a window reload.
This should be avoided since the reload will, as expected, creating various issues such as losing states.

Here is a sandbox displaying this issue.
https://codesandbox.io/s/create-next-app-example-forked-xm1jn

It's using two markdown editors for comparison purposes.
If you click in "Other editor" first, the app is not reloading and is working as expected; after this, if you click on "Uiwjs" the app will be reloaded and the console will log "APP WILL RELOAD" (triggered by beforeunload event).

• This only happens the first time you open the editor after booting the app (I believe that in the following the page is prefetched);
• I'm not sure if this happens in production, but at least in development mode it's an issue;

Reproduce the first-open behavior using the linked CodeSandbox, then trace the editor's initial-load path and the source of the beforeunload-triggering reload. The issue names no repository files or tests; done means opening the editor after boot no longer reloads the window or loses application state.