Data requested from sensors returns null

I am relatively new to Connect IQ, although I have a strong background in Android development. My goal is to send accelerometer data from my watch to my phone for data analysis. I have registered a listener for the gyroscope, magnetometer, and accelerometer. About 50% of the data received by the callback is completely null. Why is this? My sample rate is the fastest allowed by the watch (so that shouldn't be an issue) and I can't seem to find anything online about this issue. In the docs it says that the only reason that data would be null is if I didn't request it, although in the code provided below I clearly enable it.

Code: https://paste.helpch.at/utexaretig.js

Just for testing, I am only sending accelerometer data over to my phone (although I ask for gyro and mag as well). Have not tested with the other sensors. 

What am I doing wrong?