Yeah, I reproduced it. It something that crept into the code due to a change between 3.4.9 and 3.5.1 - I've tracked it down a bit and have forwarded my findings to the developer and am waiting on a reply from him.
Interestingly, it only happens to the <Hn>...</Hn> and doesn't effect other HTML codes like center or strong
Jan 12, 2012, 07:24 PM
56 posts · May 2009
Wow! glad you tracked it down. I noticed the issue accidentally, by running validator.w3.org, and this was such a minor issue I doubted whether to post it to the forum at all.