I have MC and SC connected using the MC Connector App, using the "Salesforce Data" entry, I inserted newly inserted Contacts straight into my Journey. I've noticed when I set the Default Address (in Journey Settings) to "Use email attribute from Contacts" then any new Contacts are not automatically added to the All Subscribers list, they also do not receive any comms.
Is this expected behavior? When set to "Use email attribute from Entry Source", the Contact is automatically added to the All Subscribers list if they dont exist already.