When a new installation of TIG is completed, the maximum number of records available for export is set to 5000 rows by default. To change this setting, you will need to update the config.json file in the "mapSMConfig" section (approximately line 202 in the file). Look for "maxRecordsForExport": 5000 and change to a more appropriate value for the situation.
Once the change is complete and saved, make sure to restart the IIS Server.