Cancel Order Not Updating Inventory

After cancelling the order from Commerce Manager, the inventory of the relevant product is not updating (not incrementing). 

Is there any reason for this issue ?

When I dig further by implementing AdjustInventoryOrRemoveLineItem method, I found that OperationKeys are not available in shipment parameter passing to AdjustInventoryOrRemoveLineItem method.

is there any reason for NOT having OperationKeys ?