The ticket export takes into account the merged tickets which are not included in the count for the reports.
For example, if three tickets are merged together, the reports will see that as one ticket; whereas the ticket export would see them as separate tickets. This is one of the reasons for a discrepancy in ticket count.
Another reason would be that the reports are not live. Report metrics will be updated once every 1 hour for Estate plans and half an hour for Forest or every four hours - Garden and every 24 hours for the other two plans.
If you continue to face issues, you can send an email to support@freshdesk.com with details of your issue and we'll look at it right away.