Severe barometer (altitude and vertical speed) fluctuations


In Mission Planner, is it normal that the altitude fluctuates back and forth constantly between -1m and +0.5m with a Pixhawk lying flat on a desk, connected through USB? Firmware is ArduPlane 3.7.1, MP is v1.3.48. Or is my barometer bust?

It’s very similar to this video (although this is not mine):