BT Navigator returns success before controller server completes goal

edit

I tried to make my own version of waypoint follower for Navigation2 (based on the original waypoint follower of Nav2).

I sent a goal towards (13.00, -19.00) when the robot was currently at (10.00,-22.00). As soon as the goal was sent, the BT navigator returned success to the waypoint follower client even before the controller server could say it reached the goal. After getting the result from BT Navigator, my client then sends the next new goal to (13.00, -22.00) and the robot can then be seen moving towards (13.00, -22.00).

I would like to know why BT navigator returned success before controller server could return success to it?

[bt_navigator-7] [INFO] [1614658659.534239672] [bt_navigator]: Navigation canceled  
[bt_navigator-7] [WARN] [1614658659.534265326] [bt_navigator]: [navigate_to_pose] [ActionServer] Client requested to cancel the goal. Cancelling.  
[controller_server-4] [INFO] [1614658659.554821303] [controller_server]: Goal was canceled. Stopping the robot.  
[controller_server-4] [WARN] [1614658659.554880670] [controller_server_rclcpp_node]: [follow_path] [ActionServer] Client requested to cancel the goal. Cancelling.  
[bt_navigator-7] [INFO] [1614658688.593268501] [bt_navigator]: Begin navigating from current location to (13.00, -19.00)  
[controller_server-4] [INFO] [1614658688.594426609] [controller_server]: Received a goal, begin computing control effort.  
[bt_navigator-7] [INFO] [1614658688.603655058] [bt_navigator]: Navigation succeeded  
[bt_navigator-7] [INFO] [1614658688.793412572] [bt_navigator]: Begin navigating from current location to (13.00, -22.00)  
[controller_server-4] [WARN] [1614658688.825014607] [controller_server_rclcpp_node]: [follow_path] [ActionServer] Aborting handle.  
[controller_server-4] [INFO] [1614658688.844693639] [controller_server]: Passing new path to controller.  
[controller_server-4] [INFO] [1614658689.894619821] [controller_server]: Passing new path to controller.