Hi,
I don’t see any issue in your rule. I tested with two CC emails with ; separator in a UPD3 enviromant but it works as well.
Yet, I found this bug fix 146470 and it describes your issue and it’s fixed for UPD4.
http://lcs.corpnet.ifsworld.com/login/secured/buglnw/BlBug.page?BUG_ID=146470
Try applying that and see if it resolves the issue.
I see that you are sending this to outside emails. Maybe they are filtered. Try giving an email which is in the same domain. For example if you are an IFS employee give your email as TO and FROM and give another IFS employee’s email address in CC field.
Regards,