Flowfield sum calculation


I'm facing problem flowfield. In my Item table, Inventory field is a flow field. All records in this field working fine except one record not showing correct value. While I'm checking field lookup, it is showing all correct records and if I sum all records, the value is 0. But in this table, Inventory field not showing correct value. So basicly the flowfield calculation is wrong.

Do anyone know why this is happening. please help.