From the activity logs of the lead, you can observe the following:
1. Send Email activity happened on Jan 8th 12:01 AM PST. This is when Marketo issued the Send request to the server, which held the request until 8:00 PM PST, per the time zone restrictions.
2. Email Delivered happened on Jan 8th 8:00 PM PST. The MTA (message transfer agent) pushed the held emails to the receiving servers.
The send email event is an indication that the lead was qualified at 12:01AM but the actual delivery of the email happened at 8:00 PM. So, the send event means the leads were processed and prepared for email delivery. The delivery event is when the email is actually sent and delivered. You will see this behavior when emails are sent with time zone restrictions.