Hi Philtkp,
Not sure what else to tell you about the IMU. When you say erratic, not sure. Is the I2C not working correctly? Is the IMU screwing up? Like does it want a higher voltageor current to run on than you are giving it? How are you powering Edison? ...
I know that some USB 3 drivers have been not as reliable in the past and I have had some devices that worked better when I plug them into a USB 2 port, but I really don't know very much here. Maybe others?