Alerts in Plesk GUI about system reboot should show the actual system reboot timestamp
I really like the Plesk notification of when the server has been restarted. However, the bell icon on the top right corner of Plesk shows this notification with the timestamp of logging in to Plesk. This should be the time the server actually restarted in my opinion.
This false positive notification is a product issue that will be solved in one of the nearest updates.