If there is an @ within quoted text inside of an expression, the debug action on the Editor Detail view displays N/A. If it is removed, it displays the text on Win.
'email@example.com' returns N/A.
We are using to allow an administrator user dynamically calculate the email they want to assign to the email the system sends out.
at runtime, the expressions with the full email does work properly. just not while in the Expression Editor using the Debug Action.