@Tanjamuse,
That story consists entirely of broken image tags. AO3 even reports it as 0 word length.
The 'text' you see in the browser is actually the img alt/title text. Example:
Code:
<img title="Rodney's never been one for the post-it notes, because it takes more time to write things down than it does to type them up. Long hand is just not something he does anymore." src="http://dl.dropbox.com/u/2436187/homesickness/p01.JPG" alt="Rodney's never been one for the post-it notes, because it takes more time to write things down than it does to type them up. Long hand is just not something he does anymore." data-pagespeed-url-hash="2690789119" onload="pagespeed.CriticalImages.checkImageForCriticality(this);"/>
FFF is unable to download the broken images, but it does preserve the alt attributes.
I doubt it would help, but you could try adding this to your personal.ini to also preserve the title attributes:
add_to_keep_html_attrs:,title
So, FFF is functioning as intended, the 'story' is basically broken.