Email Summary Audit Report (CSV) (aka email log) trustworthy?

Hi, is there any known issues with "Email Summary Audit Report (CSV)?"

For example, if I assign a training to someone (as Admin), then run this report right away, would I be able to see the email being logged in the report right away, or would there be a delay?

I just did a quick testing by assigning a training to myself. Our APM (Automatic Processes > Learning Plan Email Notification) is set to run hourly. After I assigned the training to myself (at 6:40pm), at 7:01pm I got the email notification. However, at around 7:05pm I ran the "Email Summary Audit Report (CSV)" and I couldn't find my email in the log. Any idea? Thanks!