My graph went wild! What causes this?

On Galaxy Nexus and few Motorola devices, you may be experiencing an issue that the sleep graphs turns wild at a specific hour during all tracking.

There is a known bug in acceleremeter which is causing the accelerometer data to go wild whenever any other app touches the accelerometer and sets it to mode DELAY_NORMAL. The apps we know about are triggering this is Noom Weight Loss and Noom Pedometer. But in general, although we are not sure, we believe this may be triggered by any other app which is using the accelerometer.