In earlier versions (V10 and older), the script statement :ADD_ATT (https://docs.automic.com/documentation/webhelp/english/AWA/12.1/DOCU/12.1/AWA%20Guides/help.htm#AE_AWA_Source/Script/ucabgs.htm) could add more email-addresses to a notification object using this syntax:
In fact, this was not the correct behavior. If you look at the documentation (link above), it states: It (script statement :ADD_ATT) adds the specified user, user group or email address to the list of recipients that should be notified
I.e., it can always add only one address. But it can be called several times. In V12, use it like that:
:ADD_ATT RECIPIENT, 'firstname.lastname@example.org'
:ADD_ATT RECIPIENT, 'email@example.com'
Then the Notification-Object goes to both recipients.