In Microsoft Exchange Server 2019 or Exchange Server 2016, when an email message contains special characters, such as <, >, &, and so on, they aren't encoded in the server generated RTF. As a result, the email message will miss some text. For example,
Have penicillin <500 mg per day.
This issue occurs in one of the following scenarios:
When you move message from primary mailbox to online archive.
When you move a message back from an archive mailbox to the primary mailbox (cached).
When you move a message from a shared mailbox (in online mode) to the primary mailbox (cached).
Note: In this scenario, using cached mode for the shared mailbox can be a workaround.
The encoding of special characters isn't preserved during the conversion from html to rtf, which causes missing text in Outlook.
To fix this issue, install one of the following updates:
For Exchange Server 2019, install the Cumulative Update 9 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019.
For Exchange Server 2016, install the Cumulative Update 20 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
Learn about the terminology that Microsoft uses to describe software updates.