We are also seeing this issue on rare occasions. But I did not suspect Cutesoft.  Sometimes it ends up in a footer we append that part of the email is not generated by CuteSoft.  Here is part of an offending email in yellow as an example output, note the ! should not be there.

 

Peachtree-Du! nwoody Road

 

You could try the suggestions in the posts on this page http://www.systemwebmail.com/faq/4.4.5.aspx

 

Jason