OK, good - we're on the right track.
Something is happening in the way it's being packaged - similar to my situation - it sounds from your description that some part of the message is being seen as an attachment object, when it is not, and therefore it doesn't show as text or attachment.
First cousin to my symptoms, same illness - that's my good guess.
If you want:
- send yourself a test email, just a few lines - test1, test2
- confirm can read on desktop, not phone
- on your desktop email look for an option to view message source, you're liable to see a bunch of html codes
- post it here, with these caveats:
Go to advanced posting - near the upper right is a little tool with <> signs - it gives you a little area to past HTML into without mucking things up
- preview before posting, so you can be sure to erase your email info, you don't want that in public
If that part is hard, drop it into a PM for me - I'm staff, I can be trusted with email info (I'll hard-delete it).
Hopefully - I may be able to spot an option that can be invoked on the other (sending) end so this problem goes away for you.
It's quite rare, but happens.