ros_canopen with joint_position_controller does not work

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Hello,

I have successfully implemented joint_velocity_controller on my Maxon motor, which works pretty well. In my final setup, I plan to use joint_position_controller. Unfortunately, when I launch nodes with joint_position_controller, after rosservice call /steering_motor/driver/init the motor start to run itself to a certain position value, even though my position commands is 0. Moreover, when the motor stops at that "spontaneous" position, it does not react to any of my manual position control commands. There is also an EMCY error message: 81#2032040000000000 , does anyone know what it refers to? Do you know where this "initial" position command might come from?

Launchfile:

<?xml version="1.0"?>

<launch>  

  <param name="robot_description" command="$(find xacro)/xacro.py '$(find maxon_canopen)/urdf/robot.urdf'" />
  <node ns="steering_motor" name="driver" pkg="canopen_motor_node" type="canopen_motor_node" output="screen" clear_params="true"  required="true" launch-prefix=""> 
     <rosparam command="load" file="$(find maxon_canopen)/config/can0.yaml" />
     <rosparam command="load" file="$(find maxon_canopen)/config/maxon_driver.yaml" />
  </node>

  <!-- Load joint controller configurations from YAML file to parameter server -->
  <rosparam file="$(find maxon_canopen)/config/controllers.yaml" command="load" ns="steering_motor"/> 

  <!-- load the controllers -->
  <node name="controller_spawner" pkg="controller_manager" type="controller_manager" respawn="false"
      output="screen" ns="steering_motor" args="spawn
                                                joint_state_controller
                                                joint_position_controller"/>

</launch>

driver.yaml

name: steering_motor

defaults:
  eds_pkg: maxon_canopen
  eds_file: "config/steering_config_3.dcf"

  #the following scaling is due to 16bit value range limitation of velocity command in vl mode (2)
  #vel_to_device: "rint(rad2deg(vel)*250)"
  motor_allocator: canopen::Motor402::Allocator # select allocator for motor layer
  switching_state: 1 # (Operation_Enable), state for mode switching

  #overflow: 0
  #dcf_overlay: 

  #  "606B": "1" # vl dimension factor numerator
  #  "606C": "24000" # vl dimension factor denominator
 # list of objects to be published (one topic per node)
  publish: [607A]

nodes:
  arm_1_joint:
    id: 1

can.yaml

bus:
  device: can0
  baudrate: 500K  
  diagnostic_period: 10
sync:
  interval_ms: 10
  overflow: 0
heartbeat: # simple heartbeat producer, optional!
  rate: 20 # heartbeat rate
  msg: "1#05" # message to send, cansend format: heartbeat of node 127 with status 5=Started

controller.yaml

joint_state_controller:
    type: joint_state_controller/JointStateController
    joint: arm_1_joint
    publish_rate: 50
    required_drive_mode: 1

joint_position_controller:
    type: position_controllers/JointPositionController
    joint: arm_1_joint
    required_drive_mode: 1

joint_velocity_controller:
    type: velocity_controllers/JointVelocityController
    joint: arm_1_joint
required_drive_mode: 3

A snippet of a terminal after launchfile, which shows successful initialization:

SUMMARY
========

CLEAR PARAMETERS
 * /steering_motor/driver/

PARAMETERS
 * /robot_description: <?xml version="1....
 * /rosdistro: melodic
 * /rosversion: 1.14.11
 * /steering_motor/driver/bus/baudrate: 500K
 * /steering_motor/driver/bus/device: can0
 * /steering_motor/driver/bus/diagnostic_period: 10
 * /steering_motor/driver/defaults/eds_file: config/steering_c...
 * /steering_motor/driver/defaults/eds_pkg: maxon_canopen
 * /steering_motor/driver/defaults/motor_allocator: canopen::Motor402...
 * /steering_motor/driver/defaults/publish: ['607A']
 * /steering_motor/driver/defaults/switching_state: 1
 * /steering_motor/driver/heartbeat/msg: 1#05
 * /steering_motor/driver/heartbeat/rate: 20
 * /steering_motor/driver/name: steering_motor
 * /steering_motor/driver/nodes/arm_1_joint/id: 1
 * /steering_motor/driver/sync/interval_ms: 10
 * /steering_motor/driver/sync/overflow: 0
 * /steering_motor/joint_position_controller/joint: arm_1_joint
 * /steering_motor/joint_position_controller/required_drive_mode: 1
 * /steering_motor/joint_position_controller/type: position_controll...
 * /steering_motor/joint_state_controller/joint: arm_1_joint
 * /steering_motor/joint_state_controller/publish_rate: 50
 * /steering_motor/joint_state_controller/required_drive_mode: 1
 * /steering_motor/joint_state_controller/type: joint_state_contr...
 * /steering_motor/joint_velocity_controller/joint: arm_1_joint
 * /steering_motor/joint_velocity_controller/required_drive_mode: 3
 * /steering_motor/joint_velocity_controller/type: velocity_controll ...