Unexpected behavior for params that exist in the launch file as well as the yaml file

edit

I have a .launch.xml file that looks like this (modified from the ros2/demos talker example)

<launch>
  <node pkg="demo_nodes_cpp" exec="talker" output="screen">
    <param from="$(find-pkg-share demo_nodes_cpp)/config/temp.yaml"/>
    <param name="temp_var" value="4"/>
  </node>
  <node pkg="demo_nodes_cpp" exec="listener" output="screen" />
</launch>

And in config/temp.yaml it looks like this

/talker:
  ros__parameters:
    temp_var: 42

When I launch the node using ros2 launch demo_nodes_cpp talker_listener.launch.xml and run ros2 param get talker temp_var I get 42 instead of 4. In ROS1, the launch file param used to override the yaml one. In ROS2, however, it seems that the yaml param takes precedent.

I can get around the issue by simply NOT including the param in the .yaml and only specify it in the .launch file / pass it into the launch file as an argument, but I just wanted to make sure this behavior is expected