Dear,
The order 8862595 is OM11 order type?
The periods in IW38/IW39 /iw28/iw29 is as follows as per SAP help:
- for notifications, it is the notification date
- for completed orders, it is the reference date of the order completion
- for orders not completed, it is the order start date
Kindly check that too for order status, so that you can get the reason.
Regards,
Pardhu