Grabbing API errors doesn't show users

I'm utilizing the Usage endpoint to grab daily API errors, but I'm not getting the users generating the errors.

Below is the output I'm receiving. It's successful, just lacks the userId that the example shows to point me at who is causing the issue. I also tried the last7days and usage endpoints, but neither brought in the data. Any ideas?

Array
(
  [requestId] => e645#15c22cc2cdd
  [result] => Array
  (
  [0] => Array
  (
  [date] => 2017-05-19
  [total] => 1314
  [errors] => Array
  (
  [0] => Array
  (
  [errorCode] => 606
  [count] => 1314
  )
  )
  )
  )
  [success] => 1
)