Find this: <?php ap_answer_the_active_time(); ?> in answer.php and cut and paste right after <?php ap_answer_the_time(); ?>
Yes, it did. I think this issue is coming from WP core, not AnsPress. We do not have any code for rendering editor. New version of WordPress have many new JavaScript changes, so probably its breaking url button. I will check if there is any chnage on TinyMCE. Also try to report same issue to wp.org forum.