If there is a link to another page on the site in the first paragraph of some Content, then:
$Content.FirstParagraph outputs "[[sitetree_link id=n]]" where the link was, while
$Content.FirstParagraph(html) outputs
<a href="[sitetree_link id=n]">text-for-page-being-linked-to</a>
I am using 2.4.1 and wonder if this is a bug.