sending a mail message with a newline character in subject yields garbage

When sending a mail message with a newline character (LF) in the subject, one gets garbage.

For instance: echo test | mutt -s foo$'\n'bar $USER@localhost

One gets a mail with just "foo" in the subject and a body that starts with "bar" and continues with some of the headers.

I don't know how this should be handled, but this shouldn't give garbage.