If you subscribe to a topic in the Spanish support forums you'll receive emails with the wrong encoding in the subject line.
Things like this will pop in your inbox:
I have noticed that this also happens in the English forums but seems limited to HTML escaped entities like apostrophes:
"[WordPress.com Forums] colors won't change"
I'm by no means an expert in MIME but I believe that the encoding is missing in the Quoted Printable tag in the subject line, at least for the Spanish forum bug:
Hope this is the right place to report it, since it's a WordPress.com thing.
The blog I need help with is diegoe.be.