Uncaught TypeError: The specifier alpinejs was a bare specifier, but was not remapped to anything. Relative module specifiers must start with ./,

Question

I am using Ruby on Rails with Import map but I got this error on Firefox 115 / Windows 8.1.

Dev console error

Uncaught TypeError: The specifier alpinejs was a bare specifier, but was not remapped to anything. Relative module specifiers must start with ./, ../ or /.

app/javascript/pages.js

import Alpine from 'alpinejs'
window.Alpine = Alpine
document.addEventListener("DOMContentLoaded", window.Alpine.start())

config/importmap.rb

pin "pages", to: "pages.js", preload: true
pin "alpinejs", preload: true # @3.13.7

Generated HTML code

<script type="importmap" data-turbo-track="reload">{
  "imports": {
    "pages": "/assets/pages-ba12da7fb4a2230da4f973acfb1fbb9f5cb6b9b812f97b24f25e9e2f1cac30fa.js",
    "alpinejs": "/assets/alpinejs-3dda3ede98a17ab1907075a7f7f92d38547a96623e9aec2946f4ba105d0d1881.js",
  }
}</script>
<link rel="modulepreload" href="/assets/alpinejs-3dda3ede98a17ab1907075a7f7f92d38547a96623e9aec2946f4ba105d0d1881.js">
<script src="/assets/es-module-shims.min-214a85aad7877320bdd7951933453829bb2ebeb97073df41719a6c5e4a10ec51.js" async="async" data-turbo-track="reload"></script>
<script type="module">import "pages"</script>
</head>

I expect working with Firefox/windows.