As far as I know about email changes if a user has changed their account email it shows up as a warning for 30 days. A 30 day warning is there to show who actually changed this email. Who actually changed the account or someone else changed it. If the original user sees it within 30 days, he can log the account if he wants.

If you want to see the accounts that have changed their email and changed their password and changed their password and email, you can check them from the logfiles suggested links below.