We have a problem when a clasified email is sent there isn't any content marking in the message body. Label policy has set a footer text but no such a text is displayed in the message (in the sent folder or in the inbox for a receiver). Do you have an idea where the problem could be? What part of the solution is responsible to add the content marking - client (Outlook) or Exchange (server)? For Office documents content marking works just fine.
Exchange On-premise 2016
No RMS connector
Microsoft 365 Apps for Enterprise (current release)
Sensitivity labels and policy applied
Licensed with Microsoft 365 E3
Labels are visible in Outlook
Label metadata is stored in the email message when the email is clasified