PX4 I2C Airspeed Sensor

Hi, if someone can suggest anything:
I have 3 devices on my I2C bus: external compass, LED and Airspeed Sensor.
all devices work correctly when powered from USB and AS shows 1-2m/s in still air.
however, when powered from lipo through apm power module Airspeed Sensor fails to initialize.
If I power PX4v1 from USB first, than connect lipo, AS jumps to 5-6m/s and stays there.
p.s. power module voltage verified at 5.27v.