Avaliable quanity of the Batch

Hi

We have Batchmanagement configured here, When i am creating delivery > Batch split > Batch Determination > AVAILABLE Quantity .

HERE the system is showing the Available quanity as 999999999999999.

Plz guide me as why the system is showing the available quanity as 999999999999 as unlimited.

As i have done the GR of 50 units. its should show only 50 as the available quantity

Where i have made the mistake plz guide.

Thanks