Suggested theme hook doesn't get applied The custom theme hook (abacus-product.html.twig) I've appended via a hook function doesn't get applied. But it shows up in the suggestions.

&lt;!-- THEME DEBUG --&gt;
&lt;!-- THEME HOOK: 'page' --&gt;
&lt;!-- FILE NAME SUGGESTIONS:
   * abacus-product.html.twig
   * page--taxonomy--term--5.html.twig
   x page--taxonomy--term--%.html.twig
   * page--taxonomy--term.html.twig
   * page--taxonomy.html.twig
   * page.html.twig
--&gt;
&lt;!-- BEGIN OUTPUT from 'themes/abacus/templates/page--taxonomy--term--%.html.twig' --&gt;


abacus-product.html.twig is in the same directory as page--taxonomy--term--%.html.twig 

Edit
This is the hook function:

function abacus_theme_suggestions_page_alter(array &amp;$suggestions, array $variables) {
    $path = \Drupal::service('path.current')-&gt;getPath();
    if (0 === strpos($path, '/taxonomy/term/')) {
        $weight = \Drupal::routeMatch()-&gt;getParameter('taxonomy_term')-&gt;getWeight();
        if ($weight == 0) {
            $suggestions[] = 'abacus-product';
        }
    }
}
EDIT, after further debugging (see comments):

Using $suggestions[] = 'page__abacus__product' and a template called page--abacus--product.html.twig works. Theme suggestions should contain double underscores.