Thanks for the reply. All of the content is new. (This is our first time running the streams so I could totally be overlooking something or confused so please just let me know).
In the Leads view it makes it look like they've been sent the content:
and same in the dashboard (although in the dashboard it doesn't have the 326 for email 2??):
But then in the Engagement Stream Performance Report (all time) it shows only the second: