1. Go To Admin>>Organization and click on Working Days
2. Un-check Sunday.
3. Change 'Payment Due On Non Working Days' from 'same day' to 'Move to Next Working Day' or any other parameters.
4. Click on Submit button.
5. Go Back to Admin>>Organization>>Working Days
You can observe that 'Payment Due On Non Working Days' remains as 'same day' though we changed it to other parameters like 'Move to Next Working Day' , etc.
Note: This issue doesn't appear every time but still exists. You can check it by frequently changing 'Payment Due On Non Working Days'