Set_position_taget_local_ned not recerived\parser by arducopter

I am using optical flow and lidar. Loiter works fine and responds well to MANUAL_CONTROL(#69) mavlink commands.
I am now trying to send SET_POSITION_TARGET_LOCAL_NED messages at regular intervals to the flight controller, from a companion computer, however they seem to not get parsed, as they do not appear on mavlink inspector.
I set the home position using SET_GPS_GLOBAL_ORIGIN.
AC version is 3.6.12

Am I missing a step somewhere?

SO, as I understand now - since SET_POSITION_TARGET_LOCAL_NED has target_system and target_component fields, the message is not forwarded to the GCS and therefore it is not visible on mavlink inspector.