Local Pose does not update from Mocap


I am trying to perform indoor flgiht with quadcopter using OptiTrack System.

I have disabled barometer, vision etc in PIXHAWK parameter to just use the result from mocap. However, only position x and position y got updated (mocap pose = local pose). The Z value keeps getting more and more negative over time. In addition, the orientation does not match either. Does anyone encounter similar issue?