Yes, same symptoms. With the letters and the blockquotes.
EDIT: Also, it's not consistent for me even on this page. I can see the 'c' (letter after 'b') in "blockquotes" in your post that I replied to, and in a few other comments, including mine, but not in the original post.
All of a sudden the letter 'c' (the one after 'b', in case it doesn't render) is not showing up in articles on Less Wrong for me, in any browser, except in images. I see a 'c' in the word 'discussion' above, but not in the body text of posts like this one or this one. Is anybody else getting the same issue?