Pixhawk and digital airspeed sensor

Hello,

I stopped using my 4525D digital airspeed sensor as it would not work after I changed to plane 3.8, so I plugged it in yesterday to see if it would start working, it is showing some air speed although a good way off the ground speed.
My real problem is when I fly with the sensor connected the wings oscillate left and right very fast making me worry this may induce some flutter. I landed and unplugged the sensor then launched again no airspeed reading and the oscillation stopped

Any possible causes/solutions please
Rich