tracking code generation does not respect subdirectories in piwik url

I have a piwik install at https://petermolnar.eu/piwik
The WP install is set up as:

Piwik URL (REST API) => "https://petermolnar.eu/piwik/"

The generated code in WP-Piwik is:

<!-- Piwik -->
    <script type="text/javascript">
      var _paq = _paq || [];
      _paq.push(['disableCookies']);
    _paq.push(['trackPageView']);
      _paq.push(['enableLinkTracking']);
      (function() {
        var u="//petermolnar.eu/";
        _paq.push(['setTrackerUrl', u+'piwik.php']);
        _paq.push(['setSiteId', 1]);
        var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
        g.type='text/javascript'; g.async=true; g.defer=true; g.src=u+'piwik.php'; s.parentNode.insertBefore(g,s);
      })();
    </script>
    <!-- End Piwik Code -->

While the code in Piwik itself is the following:

<!-- Piwik -->
    <script type="text/javascript">
      var _paq = _paq || [];
      _paq.push(['trackPageView']);
      _paq.push(['enableLinkTracking']);
      (function() {
        var u="//petermolnar.eu/piwik/";
        _paq.push(['setTrackerUrl', u+'piwik.php']);
        _paq.push(['setSiteId', 1]);
        var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
        g.type='text/javascript'; g.async=true; g.defer=true; g.src=u+'piwik.js'; s.parentNode.insertBefore(g,s);
      })();
    </script>
    <noscript><p><img src="//petermolnar.eu/piwik/piwik.php?idsite=1" style="border:0;" alt="" /></p></noscript>
    <!-- End Piwik Code -->

Check the var u=; line difference.

https://wordpress.org/plugins/wp-piwik/