When forwarding as attachment to a mail which has no or wrong charset label, although to the original mail, the user can correct the view either by selecting the charset menu or assign a correct folder charset, there is no way to assign or correct the charset of forward as attachment mail. Steps to reproduce: 1. Launch Mail. 2. Select a non-ASCII mail with no or wrong charset label. 3. Select right folder charset to the folder. 4. Highlight the mail in the folder, select Message | Forward as |attachment. On the forward compose window, since there is no charset inherited from folder, the non-ascii chars are garbled. Selecting Charset menu to the right one doesn't correct the view, although the window title or charset menu shows you have selected the right charset for the compose window. After the mail is received, the forwarded mail is garbled.

Is this about headers or body?

Both.

This is a dup of bug 66098. I have a patch there for forward attachment case. *** This bug has been marked as a duplicate of 66098 ***

Verified Dupe...

Bug 66098 is only about header, how about body handling?

Bug 41009 is about charset override for mail body. Will it take care of forward as attachment as well?

Forward as attachment, we just forward the body as attachment not changing a charset.