The difference in behaviour only occurs in r14.1 if the following option is installed.
Administration tab > Options Manager > Email > mail_show_to_cc_list
After the mail_show_to_cc_list option is installed, a single email will be sent to multiple recipient email addresses. If the option is not installed, the behaviour is the same as the previous versions of the product. If a notification is sent to 3 recipients, then 3 individual email notifications are sent.