I started seeing this issue in webmail after we upgraded from 9406 (currently on 9455 on Windows Server). 

if i open the email on my phone via my email app, it shows the email fine. I tried forwarding to hotmail, and hotmail stripped out all the HTML elements and left it straight text but it did show (which is odd because the email originated FROM outlook). In my webmail, if i switch to "View Text" the email shows up (minus styling), so there is content, only the "View HTML" option doesn't seem to work.

The strange part is, i receive emails from this client constantly, and out of 50 emails in the past 2 weeks, only 3 have had this issue.

Anyone seen this before, and have any suggestions?