When using HTML emails, reports that include the Communication: E-mail Text field will include HTML tags in their content.
It would be expected that the email message should jsut display plain text, as opposed to formatted text, or HTML tags.
If filing inbound emails, then the mail type could be changed to Text prior to filing the email. When sending emails from CRM, plain text emails could be used. This workaround requires a degree of administrative overhead.
If using on-premise copy of CRM, then a workaround using a user-defined function to save a cleansed email body to a custom field could be investigated. This value could be inserted using a table level script on the Communication entity. Once created, this field could then be used for report contents. Further details of this user-defined function are available here:
This issue has been raised to the Development team for assessment.