Yoast SEO title displaying %% in browser

Question

We have a script that displays the Yoast SEO title and if no SEO title exists, then we just default to the page title:

function replace_wp_title_with_yoast_seo_title($title) {
        
        $yoast_title = get_post_meta(get_the_ID(), '_yoast_wpseo_title', true);

        if (!empty($yoast_title)) {
            // If Yoast SEO has a title, use it
            return $yoast_title;
        }

    // If Yoast SEO title is not available or Yoast SEO is not active, use the original title
    return $title;
}

add_filter('pre_get_document_title', 'replace_wp_title_with_yoast_seo_title', 10);

But in browser we something like this for the title: Marijuana Users May Eat More—But Weigh Less %%page%% %%sep%% %%sitename%%

Any ideas on why this is doing this?