On the Free plan, Mailtrack records all opens for your tracked emails but only shows you the first open. Subsequent opens are still captured in the background — they are not lost.
If you upgrade to a paid plan, you will be able to see the full open history, including any subsequent opens that were recorded before you upgraded, for emails sent within the past 7 days. Upgrading to the Mailsuite plan extends this access beyond the 7-day window, giving you access to the complete tracking history.