When a customer replies to a notification email sent by Service Desk (Cloud), all the content from the notification is often included in the comment created. Often it is stripped but often it isn't, I think it must depend on the email client the responder is using. (See https://support.atlassian.com/servicedesk/customer/portal/23/JST-132896 for an example.)

The incoming mail handlers for regular JIRA users are not used by Service Desk, nor is there any way to configure Service Desk mail handlers.

It would be great if Service Desk did a better job of stripping quoted content, either automatically or via regex as regular JIRA Cloud allows.