I do not have a solution; I have the same problem, but only on my O365 account, working from home. Working on my corporate laptop with (presumably) accessing the same O365 account, the emails ALWAYS look normal. I use Outlook 2016 currently.
SUGGESTION: Attempt to open the email with the odd characters with a web browser.
I use the Move --> Actions --> View In Browser. For me the text looks perfectly normal in the browser, which leads me to believe it is a formatting error associated with my Outlook. In this scenario, I believe Outlook converts the email to a .mht file, stripping
the offending formatting, rendering a normal output.
Other comments:
- I have sent email replies that look perfectly normal as I type them. Then they are sent with the odd characters. They show in my Sent Items with the odd characters.
- I have received attachments (Outlook messages attached to other Outlook messages) that have the odd characters. In some, the normal English shows up at the end for about 3 lines of text.
In all scenarios, my corporate laptop shows the emails as normal.
Sample characters:
Beginning of 1st line: 格浴ス惓㩳㵶ョa悵ェrオオ
Random characters in email: 蓮顫本☮ー迸セ @畢ゥù⁉慣
John