Arduino Serial delay

I am running ROS on a raspi 3 which is connected over serial to an Arduino due. It seems when I start up my ROS nodes I incur a massive delay over Serial in the arduino (the loop runs at 1-3 hz). When I remove the serial_node.py from my launch file this issue is gone, but I am unsure what the root cause is. I run the arduino and ROS at 57600 baud. Anyone experience an issue like this or have any ideas what I should look at for debugging this issue, I am a ROS noob.