Firefox Windows GPO: ExtensionSettings fails to parse

I have issues getting the ExtensionsSettings policy to parse correctly. The Firefox debug console only shows “Parsing error” with no hint as to why it fails. I have validated the json value, so the issue must lie somewhere else. But I don’t know where.

OS: Win 11 24H2
Firefox: ESR 140.0.0.2

GPO Key: ExtensionSettings
Value:

{
  "*": {
    "blocked_install_message": "Blocked",
    "install_sources": [
            "about:addons",
            "https://addons.mozilla.org/"
        ],
    "installation_mode": "blocked"
  },
  "uBlock0@raymondhill.net": {
    "installation_mode": "allowed",
    "updates_disabled": false
  },
  "{0b457cAA-602d-484a-8fe7-c1d894a011ba}": {
    "installation_mode": "allowed",
    "updates_disabled": false
  },
  "{7a7a4a92-a2a0-41d1-9fd7-1e92480d612d}": {
    "installation_mode": "force_installed",
    "install_url": "https://addons.mozilla.org/firefox/downloads/latest/styl-us/latest.xpi"
  }
}

This is supposed to block all AddOns, except uBlock Origin and FireBase, which are allowed to be installed, and Stylus, which is supposed to be force-installed.

Can anyone give me a hint as to why this doesn’t work?

Edit: relevant links:

Firefox GPO documentation: https://mozilla.github.io/policy-templates/#extensionsettings

Firefox AddOn latest download link: https://stackoverflow.com/questions/55496793/how-to-get-the-link-to-the-latest-version-of-firefox-addon#55593381

Firefox Debug console: https://support.mozilla.org/en-US/kb/debugging-policy-issues

Edit2: Removing the block with the addon to be force-installed fixes the parsing error. I don’t know why.

Edit3: working example:

{
  "*": {
    "blocked_install_message": "Blocked",
    "install_sources": [
            "about:addons",
            "https://addons.mozilla.org/"
        ],
    "installation_mode": "blocked"
  },
  "uBlock0@raymondhill.net": {
    "installation_mode": "allowed",
    "updates_disabled": false
  },
  "{0b457cAA-602d-484a-8fe7-c1d894a011ba}": {
    "installation_mode": "allowed",
    "updates_disabled": false
  }
}