trouble adding two menus to the same page

Hello,
I am having trouble adding two menus to the same page. I have created the menu locations and registered the menus via functions.php. I have also created menu items for both menus.

function register_new_nav_menus() {
    register_nav_menus( array(
'header-menu' => __( 'Header Menu' )
'filter-menu' => __( 'Filter Menu' )
    ));
}
add_action( 'init', 'register_new_nav_menus' );

I then call each menu via a separate function:

function filter_menu() { ?>

    <div class="rainbow-bar">
        <div class="rainbow1 rainbow" style="height: 100%; opacity: 1;"></div>
        <div class="rainbow2 rainbow" style="height: 100%; opacity: 1;"></div>
        <div class="rainbow3 rainbow" style="height: 100%; opacity: 1;"></div>
        <div class="rainbow4 rainbow" style="height: 100%; opacity: 1;"></div>
        <div class="rainbow5 rainbow" style="height: 100%; opacity: 1;"></div>
    </div>

     <div class="navigation">
        <nav>
            <ul class="nav">
                <?php if (get_field('logo_option', 'option') == "Text") { ?>
                <li class="logo">
                    <a onClick="location.href='<?php echo home_url(); ?>'">
                        <?php the_field('logo_text', 'option'); ?>
                    </a>
                </li>
                <?php } ?>
                <?php if (get_field('logo_option', 'option') == "Image") { ?>
                <li class="logo-image">
                    <a onClick="location.href='<?php get_bloginfo('url') ?>'">
                        <img src="<?php the_field('logo_image', 'option'); ?>"/>
                    </a>
                </li>
                <?php } ?>
                <?php $defaults = array(
                        'theme_location'  => 'filter-menu',
                        'menu'            => '',
                        'container'       => '',
                        'container_class' => '',
                        'container_id'    => '',
                        'menu_class'      => 'menu',
                        'menu_id'         => '',
                        'echo'            => true,
                        'fallback_cb'     => 'wp_page_menu',
                        'before'          => '',
                        'after'           => '',
                        'link_before'     => '',
                        'link_after'      => '',
                        'items_wrap'      => '%3$s',
                        'depth'           => 0,
                        'walker'          => new MV_New_Walker_Nav_Menu()
                    );
                ?>

                    <?php wp_nav_menu( $defaults ); ?>

            </ul>
        </nav>
    </div>

<?php }

However, when I call the menus from within the template using:

<?php header_menu(); ?>
<?php filter_menu(); ?>

only the last menu called is displayed. For example, if I put header_menu(); last then the header menu shows. If I put filter_menu(); last then the filter menu shows. Is two menus on the same page not possible?