Quarantine administrators are unable to preview email templates from the "Show source" screen in the Symantec Email Quarantine portal > Manage Email Templates.
The Symantec Email Quarantine mailboxes currently being affected are:
https://us.quarantine.symantec.com/
https://eu.quarantine.symantec.com/
The current workaround is to change the screen view from "Show source" to "Show Wysiwyg" before previewing the email template changes.
This has been raised to our development to fix this bug in our production environment.