I have this custom wp_trim_words() function set to give me excerpts of only 20 words, and for the most part, it works fine. Except for some reason, on posts that contain lists, it outputs way more than 20 words. (See the posts at the bottom of this page.) How can I fix this? I tried removing <ul>,<ol>,<li>, from the function insight_allowedtags() but that did nothing.

Ideally, I’d like to make the custom excerpt output at least 20 words and end at the end of a sentence regardless of whether or not the post contains a list.

This is the custom function I am using (as suggested in this post):

// Custom Excerpt for Insights Posts on Insights Page & Category Pages
function insight_allowedtags() {
    // Add custom tags to this string
        return '<script>,<style>,<span>,<ul>,<ol>,<li>,<a>,<p>'; 
    }

if ( ! function_exists( 'insight_custom_wp_trim_excerpt' ) ) : 

    function insight_custom_wp_trim_excerpt($insight_excerpt) {
    global $post;
    $raw_excerpt = $insight_excerpt;
        if ( '' == $insight_excerpt ) {

            $insight_excerpt = get_the_content('');
            $insight_excerpt = strip_shortcodes( $insight_excerpt );
            $insight_excerpt = apply_filters('the_content', $insight_excerpt);
            $insight_excerpt = str_replace(']]>', ']]&gt;', $insight_excerpt);
            $insight_excerpt = strip_tags($insight_excerpt, insight_allowedtags()); /*IF you need to allow just certain tags. Delete if all tags are allowed */

            //Set the excerpt word count and only break after sentence is complete.
                $excerpt_word_count = 20;
                $excerpt_length = apply_filters('excerpt_length', $excerpt_word_count); 
                $tokens = array();
                $excerptOutput = '';
                $count = 0;

                // Divide the string into tokens; HTML tags, or words, followed by any whitespace
                preg_match_all('/(<[^>]+>|[^<>s]+)s*/u', $insight_excerpt, $tokens);

                foreach ($tokens[0] as $token) { 

                    if ($count >= $excerpt_word_count && preg_match('/[,;?.!]s*$/uS', $token)) { 
                    // Limit reached, continue until , ; ? . or ! occur at the end
                        $excerptOutput .= trim($token);
                        break;
                    }

                    // Add words to complete sentence
                    $count++;

                    // Append what's left of the token
                    $excerptOutput .= $token;
                }

            $insight_excerpt = trim(force_balance_tags($excerptOutput));

                // $excerpt_end = ' <a href="'. esc_url( get_permalink() ) . '">' . sprintf(__( 'Read more about %s &nbsp;&raquo;', 'wpse' ), get_the_title()) . '</a>'; 
                // $excerpt_more = apply_filters('excerpt_more', ' ' . $excerpt_end); 

                //$pos = strrpos($wpse_excerpt, '</');
                //if ($pos !== false)
                // Inside last HTML tag
                //$wpse_excerpt = substr_replace($wpse_excerpt, $excerpt_end, $pos, 0); /* Add read more next to last word */
                //else
                // After the content
                $insight_excerpt .= $excerpt_end; /*Add read more in new paragraph */

            return $insight_excerpt;   

        }
        return apply_filters('insight_custom_wp_trim_excerpt', $insight_excerpt, $raw_excerpt);
    }

endif;

remove_filter('get_the_excerpt', 'wp_trim_excerpt');
add_filter('get_the_excerpt', 'wpse_custom_wp_trim_excerpt', 'blog_custom_wp_trim_excerpt', 'event_custom_wp_trim_excerpt', 'insight_custom_wp_trim_excerpt'); 

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