well i figured a work around. if you switch to source, you can edit the <a href to display the email address and still link to the mailto, and pre-entered subject line. for me this technically was easy, but we are using this on our site with numerous members not sure all will be as savy, its definitely a bug since the ck editor has the layout when you open the link box, then change to EMAIL, but it displays all the coding when it should only display the email!
Re: CKEditor 3.3.1 (rev 5586) How to hide Mailto & subject l
Re: CKEditor 3.3.1 (rev 5586) How to hide Mailto & subject l
http://ckeditor.com/demo