API: Inconsistent Results on User Lookup

I'm seeing an issue where certain users won't be found when looking up their GitHub, Reddit, or Twitter usernames via the API. Strangely, for the examples with malgorithms, these calls work just fine, while they return an empty "them" array rather than the user I expect. This is both through a Python API interface and the browser fields.

As an example, trying:

`https://keybase.io/_/api/1.0/user/lookup.json?github=codinganarchy&fields=basics`

returns:

`{"status":{"code":0,"name":"OK"},"them":[],"csrf_token":"lgHZIDMwMjM5MWJlZWIyODIzMTFmNjZjNTZiMzRlODgxYzAwzlTApFDOAAFRgMDEIMZNiUEMnIRk2q7VA9ntJ4khM9ZvB6TALpHhjLosn4zT"}`

when it should return my keybase username (`thorodinson`) and details.

Start by reproducing the API request at the provided user/lookup.json endpoint with github=codinganarchy and fields=basics, then compare the result with the browser fields and Python API interface. Done means the lookup returns the expected Keybase user and details instead of an empty "them" array.

Written by the indexing model from the issue text.