Line 2 of https://github.com/Automattic/o2/blob/master/inc/tpl/post-view.php is missing the comments ID on the block, so the #comments link expected by core to be there is not working.
Change:
<div class="o2-post-comments"></div>
To:
<div class="o2-post-comments" id="comments"></div>
Reference: https://meta.trac.wordpress.org/ticket/4640