This only occurs if a trip was created BEFORE your company enabled the Commute deduction settings. If the trip is recognized as a commute trip, the only selection that you can choose from the Trip Purpose drop-down list is either "Commute" or "Personal".
Depending on your company's commute deduction setting, if your trip was recognized as a "commute" (based on the inputted home/office address) the drop-down menu will not allow a user to select "business" as an option because the recognized trip appears to be a commute trip to or from the user's home/office address. Some companies deduct a user's first and/or last trip to and/or from the home address as a commute deduction.
Kliks uses a geofence to determine if your trip has a start or end destination that matches your Home address. See this article about geofence distances.
For more information: https://www.kliks.io/