RpLidar A3 needs a little different configuration, here is provided example launch file for A3 version.
In our example
launch files we are including RpLidar with:
<include file="$(find rplidar_ros)/launch/rplidar.launch"></include>
You can change it to:
<include file="$(find rplidar_ros)/launch/rplidar_a3.launch"></include>
ros-core2-client does not matter here, as both devices are using different serial ports.