This is likely the same problem as in Over-escaping html on timeline page. On the mod history page, in the list of moderator actions, some things are escaped that shouldn't be. The page source contains things like
<span class="mod-post-actions">&#9830;&nbsp;<span title="Some Moderator Apr 2 at 11:18">Post converted to comment</span>, <span title="Some Moderator Apr 2 at 11:18">Post Deleted</span></span>
which should of course be
<span class="mod-post-actions">... and previously were.
It seems only that one class is affected.