Still a problem on a mac and much more convoluted if you throw in your iPhone don't have time to try iPad. None of the attachments at the end, plain text, fixes available that i can find. I've tried forwards and created new emails on my phone, if it passes through an email account on an exchange server and look at the emial on my phone I get a "C" extension text file, if the attachment is not at the end. if i send the same thing to my phone account works just fine.
Something seems to be happening when the mail hits the exchange server?? It does not appear to be simply a rendering issue, the email was sent from my iP4 to an email account on an exchange server and read on the same iP4 that sent it.
I've got to agree with those that are dumping this on the Apple guys. I read about this same thing happening for YEARS and it only happens with emails that originate from the Mac Mail clients.