Encoding of special characters isn't preserved which causes missing text in Outlook in Exchange Server 2019 and 2016

Symptoms

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.

will become:

Have penicillin
 

This issue occurs in one of the following scenarios:

1. When you move message from primary mailbox to online archive.

2. When you move a message back from an archive mailbox to the primary mailbox (cached).

3. 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.

Cause

The encoding of special characters isn't preserved during the conversion from html to rtf, which causes missing text in Outlook.

Resolution

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.

References

Learn about the terminology that Microsoft uses to describe software updates.