Some special characters are sometimes not decoded properly from email

I send an email to my personal notice-by-email adress $Rnd@identi.ca. Relevant
parts of the header (full mail attached):

================================================================================

Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: quoted-printable

@marjoleink
"My" email server is google - I'm using gmail web interface. So, yes,
I can eliminate this.
=84one off=93. Works now. a one off?

================================================================================

This got posted -> http://identi.ca/notice/75728544
But on the web (screenshot attached as well), the
text " =84one off=93 " is shown as "blocks". That's,
because the page is sent as UTF-8:

$ wget -S http://identi.ca/notice/75728544
--2011-06-08 10:53:53-- http://identi.ca/notice/75728544
[…]
Content-Type: text/html; charset=utf-8
[…]

If I manually switch the encoding to Windows-1252 in
Firefox, these 2 chars look better - but not by much...
See the other attached screenshot.