I'm using Rick Strahl's wwIPStuff library to send emails.

I'm sending emails (in English) encoded with Content-Type: text/html

A very small percentage of recipients are receiving emails in what appears to be Chinese (technically it would probably be Mandarin)?

Somewhere along the way it looks like the content-type is getting changed

------=_NextPart_000_00D1_01CA3BA7.8CC88850
Content-Type: text/plain;
charset="UTF-8"
Content-Transfer-Encoding: base64

------=_NextPart_000_00D1_01CA3BA7.8CC88850
Content-Type: text/html;
charset="UTF-8"
Content-Transfer-Encoding: quoted-printable


Anyone have any ideas why this is happening and/or have a fix?