OK, I'm getting confuseder by the minute.

ADC PE, you seem to be almost right. The prebuilt string does have CRLF's where expected, about every 39 characters or so, according to a Data View in DMD. I checked and the first extra CR in the email is indeed exactly 80 characters from the beginning of the message (though the second one is 180 chars after??), so you'd think maybe the EMAIL box is failing to send them and SMTP server is inserting an extra......BUT, it's only the 80th character IF YOU COUNT the <CR>'s and <LF>'s that are supposed to be there, plus the previous lines break where intended! So I know the server's getting the intended 0D0A's, so that hypothesis doesn't work.
So then I thought maybe it's a bug in that specific SMTP server (inbox.com), so I tried another email server (vfemail.net), and the received email had extra breaks in exactly the same positions. Can't be a bug in TWO servers, can it?
So then I thought maybe it's in my email client (Thunderbird), and it's just rendering that way on screen, but I looked at the message on the server using Cox's webmail client, and the extraneous breaks are already in by that point.
At this point, don't know what to do, other than put the mirroring switch on and verify what Do-More's sending, byte by byte.
Thoughts?