Hi Shakti;
Check the odata service call
http://<host>:<port>/sap/opu/odata/sap/HCM_LEAVE_REQ_APPROVE_SRV/LeaveRequestSet
to find out the value which is fetched from backend.
then try to debug and find out from where this value 26 is coming.
and for the error, is it happening for this one request or for everything.
Did you try in any other test user id.
Regards,
Sarbjeet Singh