Nested Layouts - Confused about consistency of "eager" rendering when done conditionally

[csi-lk]

Hit an interesting piece of functionality with the App Renderer I'm looking for clarification on

Note: I'm using the word eager to define doing something before it's needed, this may not be the correct terminology but I don't know what is here, so feel free to correct and i'll update the question

Context: We have a requirement for turning on and off routes with conditional logic (in our case feature flags but this part shouldn't matter)

In the docs it gives a specific example on Conditional Routing with @slots, which makes sense, the part I'm confused by is that in the example provided of:

export default function Layout({
  user,
  admin,
}: {
  user: React.ReactNode
  admin: React.ReactNode
}) {
  const role = checkUserRole()
  return <>{role === 'admin' ? admin : user}</>
}

Both the user and admin @slots pages are rendered on the server regardless of the conditional, including any server side logic (eg. making fetch calls for their respective data).

I assume next is eagerly rendering both pages on the server for speed of delivery, there's an issue here around making fetch calls when not required, but at the end of the day the rendered component going to the user is correct.

My question is, If I setup an app with

/app
  /test-conditional-rendering
    layout.tsx
    /@one
       layout.tsx
       page.tsx
    /@two
       layout.tsx
       page.tsx

The root layout.tsx has

import type { ReactNode } from "react";

const test = true;

export default async function Layout({
  one,
  two,
}: {
  one: ReactNode;
  two: ReactNode;
}) {
  console.log("layout root called");
  return <div id="container">{test ? one : two}</div>;
}

and each slot layout / page is a straightforward with a console.log of what is running

export default async function Page() {
  console.log("page @one called");
  return <div>Page @one</div>;
}

I get the output from cold boot:

page @one called
page @two called
layout @two called
layout root called
page @one called
page @two called
layout @two called
layout root called

Image of setup / for more clarity: image

My confusion is that: layout @one doesn't get called for rendering (or, at least, doesn't trigger the console.log), am I missing something obvious here?

Any guidance would be helpful

(I've run it many times in case there's a race condition here I'm missing)

[csi-lk]

Wondering if I can bump this as it's been a while without response