When sending some emails from Iphone/Ipad mail app, email arrives on Iphone mail in code. After a few min it corrects itself to what it should be display
When sending email from my Iphone using my Microsoft Exchange 365 account to another apple devices with the exchange account connected in the mail app display the email in "code" -
After a few minutes after the mail was delivered it would correct itself and the email will display correctly.
I have tested this between different apple devices using the native mail apps and they all do this on Iphone, mac and ipad
iPhone 5, iOS 9