Email With Email CC Isn't Sending to Some CC Recipients

[#1]

Issue

Issue Description
You enabled a field for email CC and it is working for some email CC recipients, but some records on the CC are not receiving the email.
 

Solution

Issue Resolution
If any of the CC email addresses are known leads in your Marketo database and marked as unsubscribed they will not receive the email, even if the email is marked as operational.