If you configure the Create Issue(s) post-function to copy all comments from the current issue to the new issue, then no COMMENT_CREATED notification should be sent out (but they should still be sent out when you add a comment to the new issue using the "set field value" options).
This also applies to the following post-functions when the "trigger updated event" option is not checked (we might want to rename it when the destination field is Comments):
Copy Field Value to Related Issues
Set Field Value of Related Issues
Data Center Server