"Pending Order Canceled" happens when:

• when the Master has placed a pending order that has been cancelled before triggered.
• when the pending order has been triggered on the Master but not on the Slave, and when the Master close the trade it cancel the pending order on the Slave

The "Pending Order Rejected" or "Pending Order Cancel Rejected" happens when the order sent is rejected for any reasons by the broker.

In all above cases, if the behavior is not as expected you are prompted to try again to place an order or to manage position manually.