This happnes because the global setting in your system called 'Absence Interface – Export Unauthorised Sicknesses' is set to False. When this setting is disabled, only closed sickness records are included in the absence export.
To amend this setting, follow these steps:
Navigate to Settings then expand the System Settings drop-down.
Click the Global menu option.
Search for Absence interface - export unauthorised sicknesses in the name field and click into this.
Within the pop-up window, you should see a field titled Boolean, change this from False to True.
Click Save.
📌Note: Going forward from the change, any open sicknesses will export when the Absence Export is run.