A work around would be to ensure that a progression step for "opened" email as a trigger is included in your program. You could then look at the timestamp for their progression status and have a general idea of when they are sent out. (Same for clicked, etc)
Also, if you're using the email blast program, there is a built in dashboard that shows when the email was opened. In order for this to work, you have to send your QA through a different program, because it includes the timeline for every smart campaign in the program.
Hope that helps!