Comment 29 for bug 691366

Thanks Mike!

Hm, now that I've got that info, I can't remember what I wanted to know the output of stream_get_filters() for! :) Looking at the code, I think maybe it's because the presence or absence of the "convert.*" filter determines whether or no phpmailer sends the email text through a particular converter function or not. But you've got "convert.*", and I've also got it on my local machine (where this code works fine) so that doesn't seem to be the cause of the problem.

I think your workaround of setting localhost:25 fixes the problem because it causes the email to be sent by class.smtp.php rather than class.phpmailer.php.

So, it looks like this is, in fact, a phpmailer bug. I see that phpmailer is up to version 5.2.6 now ( https://github.com/PHPMailer/PHPMailer/blob/master/changelog.md ). I wonder if they've solved this bug in the newer versions.