Let me throw in additional informations here:The SMTP relay we are using for sending the notifications is a google apps gmail SMTP.Our organization runs on Google suite and therefore our mailboxes are gmail based.In our gmail inbox, we can see that the time emails are sent (entering the email, accessing the email header details) are right = corresponding to the times of OSTicket actions. However the Our client's organization does not run GSuite though and they are reporting the same problem.Looks like this is solely bound to usage of Gmail SMTP. However in our experience this only happens on OSTicket since it's hosted on AWS.Weird...