However, in the 'Alert the following Support Reps by Email, when a new reply is appended to request of Unavailable(Offline) Support Rep' the  $Description field populates with only the original email that was sent it, not with the content of the reply that the contact emailed it.  

Why does the same field behave differently in the two different email templates?  I need the $Description field to populate with the actual email response from the client in the  'Alert the following Support Reps by Email, when a new reply is appended to request of Unavailable(Offline) Support Rep' template like it does in the  'Alert Support Rep by Email when there is a new reply from the contact' template.