Langswitcher update language name

Hello

Updating langswitcher plugin made language name variable {{ native_name(key)}} output as 1 or 2 instead of Engish or 日本語.
There's an issue https://github.com/getgrav/grav-plugin-langswitcher/issues/10 but no solution.
here the code of langswitcher.html.twig

<ul class="langswitcher">
{% set langobj = grav['language'] %}
{% for key in langswitcher.languages %}
    {% if key == langswitcher.current %}
        {% set lang_url = page.url %}
        {% set active_class = ' active' %}
    {% else %}
        {% set lang_url = base_url_simple ~ langobj.getLanguageURLPrefix(key)~langswitcher.page_route ?: '/' %}
        {% set active_class = '' %}
    {% endif %}
    <li><a href="{{ lang_url ~ uri.params }}" class="external{{ active_class }}">{{  native_name(key)|capitalize }}</a></li>
{% endfor %}
</ul>
--- 
Here is output:

<li>
<a href="/1" class=" external"></a>
</li>
<li>
<a href="/2" class=" external"></a>
</li>

I have also tried to see the API by myself, but was not able to find out.

As I wonder if it's not related to settings in `system.yaml` and I am not really able to understand them, please find them below for more complete information: 

languages:
supported:

• fr
• ja
• en
  session_store_active: true # Store active language in session
  http_accept_language: true # Attempt to set the language based on http_accept_language header in the browser
  override_locale: true # Override the default or system locale with language specific one
  TXTCopy

Thanks in advance for help

What version of Grav are you on? I'm not having this problem with latest Grav 1.1

1.1.1. (thank you) (in the issue linked above, Flavio is not able to recreate the problem either...)

There is a mistake in the way things are exposed in this thread so see new post please https://getgrav.org/forum#!/plugin-development:langswitcher-output-after-u