Hi,
I suggest to use
<arg name="rgbd" default="true"/>
since ICP only cannot recover from being lost. What you are seeing is that odometry is lost and odom->camera_link is not published anymore.
You can also remove
<param name="/use_sim_time" value="true"/>
as you are not using a rosbag.
Also, note sure why it works with the current launch file, but I think we should set
<arg name="depth_registration" value="true"/>
for openni.launch to get registered depth images too.
cheers,
Mathieu