We have the same problem and have not found any solution yet, it seems the email header gets broken (faulty line breaks?) after “Content-type: text/html; charset=utf8” at line 412 in /_inc/cart.php
The rest of the code seems the be interpreted as the body of the email or ignored completely, same thing happens with the download and conformation email send to the customers.
and it’s a massive bug! someone can order images and I get the email as per the above and I have no idea what they have ordered. Its like falling at the last hurdle! I there a work-around?