For sites with many many posts and/or posts with LOTS of words. Depending on server capacity, PHP may time out when trying to go through and count everything. As a workaround solution, it’s possible to disable the “all word count” shortcode by adding the following code to your theme functions.php, or add via custom plugin:
function sbs_word_count_all_disable($disable) { return true; }
add_filter('sbs_word_count_all_disable', 'sbs_word_count_all_disable');
Let me know if I can provide any further infos, glad to help anytime.