For an item onhand quantity and total item reserved is not matching

Hi,

Here is a scenario i got an ingredient let say itemA OHQ = 2000 and total reserved itemA= 1800 and if i go to material workbench and check for Available to Reserve and Available to transact its showing 0. I checked the Mtl_reservation it got reservation 1800 for that item so what about the rest 200 qty. In which table i can find the rest of quantity. I checked the subinventory and locator status, resevable everything is fine.Also the item is not lot and serial controled. Please help me to resolve this.

Thanks.