This is a limitation that affects the email tracking industry in general, not just Mailtrack.
if you re-read sent emails on your phone or another device/browser without Mailtrack installed this will generate an open alert as Mailtrack cannot tell whether our tracking pixel was downloaded by the recipient reading the mails or by the sender re-reading the emails they've sent.
With Mailtrack, though, you can normally avoid this by opening your sent emails using the same browser that you sent the email from (that has Mailtrack enabled). Because that way our service can identify that it is you and not the recipient that is reading the mails and will ignore the tracking pixel download/open.