WP Bootstrap navwalker shows desktop dropdown on mobile

I'm having some trouble with the WP Bootstrap navwalker script for Wordpress. When I'm on mobile, it shows a desktop dropdown when you click on a menu item, instead of the normal Bootstrap menu on mobile. See image here.

Here's a link for the page

My menu code:

<nav class="navbar navbar-default navbar-fixed-top">
<div class="container">
    <div class="navbar-header">
        <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
            <span class="sr-only">Toggle navigation</span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
        </button>
        <a class="navbar-brand" href="<?php bloginfo('url'); ?>"><img src="<?php bloginfo('template_directory'); ?>/assets/img/logo.png" alt="Aluproff"></a>
    </div>
    <div id="navbar" class="navbar-collapse collapse">
        <ul class="nav navbar-nav">
            <?php do_action('wpml_add_language_selector'); ?>
        </ul>
        <ul class="nav navbar-nav navbar-right">
            <?php /* Primary navigation */
                wp_nav_menu( array(
                  'menu' => 'primary',
                  'theme_location' => 'primary',
                  'depth' => 2,
                  'container' => false,
                  'menu_class' => 'nav',
                  //Process nav menu using our custom nav walker
                  'walker' => new wp_bootstrap_navwalker())
                );
            ?>
        </ul>
    </div><!--/.nav-collapse -->
</div>
</nav>

How can I fix this?

via Chebli Mohamed