Yaw at waypoint not working with Parrot Sphinx

Sending a value for yaw in parameter 4 of MISSION_ITEM_INT does not do anything. Why is this?

In the MAV_CMD_NAV_WAYPOINT ?
https://developer.parrot.com/docs/mavlink-flightplan/messages.html#mav-cmd-nav-waypoint-message-code-16

Yes. When using the Anafi4K model on the parrot sphinx simulator to test implementation of control of a Anafi USA. Do I need to change the view mode? I think the options are stepped, smooth or ROI.

Do you know what the flightplan feature does in the background to allow the platforms to fly with a crabbed motion? I can set ROI’s but unless the waypoints are very close together there is an obvious switch between pointing at the different ROI’s rather than a smooth transition between them giving the appearance of smooth crabbed flight, but if yaw doesn’t work I don’t know how else flightplan does in unless in the background it sets a lot of ROIS with delays perhaps or many hidden waypoints? Or am I missing something else?