Quantites not pdating when Bill is marked received - Bug

I create a bill using the inventory selection feature. This should align the line item on the bill to the inventory item. Before the items on the bill are revceinved I edit the item quantity in the inventory (simple inventory adjustment). When the items are received I use the Mark Item Received on the bill to accept the shipment. However, the quantity on the bill is not incremented onto the inventry.

If I do not touch an inventory before it is received, marking the bill received will cause the item quantity to update.

Seems that the bill line items are not tighlty linked to the inventory item.