Live_patch triggering mount

I am having the odd situation that live_patch seems to render full page loads.
In my .leex file:

<%= live_patch "Test", to: Routes.test_path(@socket, :index) %>

Expected behavior: handle_params/3 is invoked.
Observed behavior: mount/3 and then handle_params/3 is invoked.

My app.js:

import 'phoenix_html'
import { Socket } from "phoenix"
import LiveSocket from "phoenix_live_view"

// if we do have a crsf token (all pages except error pages)
// then connect live socket and enable various functionalities
const csrf_elm = document.querySelector("meta[name='csrf-token']")
  const _csrf_token = csrf_elm.getAttribute("content")
  let liveSocket = new LiveSocket("/live", Socket, { params: { _csrf_token } })

My router.ex:

live "/", TestLive, :index

Any ideas what could be causing full page reloads?
Looking into the developer tools, the patch link seems to be created correctly:

<a data-phx-link="patch" data-phx-link-state="push" href="/">Test</a>

You are live_patching from and to the same LiveView, right? Asking this because live_patch works for navigation within routes handled by the same LiveView, otherwise it falls back to how live_redirect works.

Yes. I do not know exactly what was the cause but cleaning my node_modules and upgrading webpack somehow did the trick. very mysterious. Thanks a lot!