pagePath not properly resolved?

[rowild]

I have a setup with this configuration:

import { resolve } from "path";
import handlebars from "vite-plugin-handlebars";

const pageData = {
  "/src/pages/index.html": {
    title: "Homepage"
  },
  "/src/pages/subpage/index.html": {
    title: "Subpage"
  }
};

const handlebarsOptions = {
  context(pagePath) {
    console.log("pagePath =", pagePath);
    return pageData[pagePath];
  },
  partialDirectory: resolve(__dirname, "src/pages/partials")
};

export default {
  plugins: [handlebars(handlebarsOptions)]
};

A codesandbox is here:
https://codesandbox.io/s/vite-with-handlebars-61te7

As the terminal shows, the console.log does not pick up the current configuration.

What am I doing wrong?