Please follow the steps as follows to resolve this error:
Go to the Leave module.
Click Setup, and click Leave Type.
Select the affected leave type and check if there is more than one leave type.
Go to Process Leave, highlight the affected leave type, and delete the leave type.
Then go to Setup, Leave Type, select the affected leave, and click Delete.
Log in to eportal as admin, and click Settings.
Select eleave setting and select Configuration.
Click Copy all leave type from EPE.
Check if the error persists.