move_base.wait_for_result always returns false

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Hi, I'm using move_base.wait_for_result(rospy.Duration) to set a time limit for robot motion. But this function always returns "false" and indicates a timeout even though the robot has actually reached the goal. I use move_base.get_state() to check the robot suatus and it shows status: 3 and text: "Goal reached.". I put the code block below for reference. Thanks in advance!

        finished_within_time = self.move_base.wait_for_result(rospy.Duration(60))   

        if not finished_within_time:  
            self.move_base.cancel_goal()  
            rospy.loginfo("Timed out achieving goal")  
        else:  
            state = self.move_base.get_state()  
            if state == GoalStatus.SUCCEEDED:  
                rospy.loginfo("Goal succeeded!")  
                n_successes += 1  
                distance_traveled += distance  
                rospy.loginfo("State:" + str(state))  
            else:  
              rospy.loginfo("Goal failed with error code: " + str(goal_states[state]))