Bug in add order history

when i add a new order history,

it will decrease the product quantity,

eg. product quantity in store after create a new order : 100 pcs
new order quantity : 3pcs

when add order history form pending to processing ,

product quantity in store will drop to : 97pcs

when add order history form processing to shiped ,

product quantity in store will drop to : 94pcs

it will not happen in Verson 1.5

I'm seeing this problem as well. Each time the order status is updated, the stock quantity is again decreased. Can anyone offer any help with this?