Upload_files UAPI call does not work when using the WHM API

Symptoms

When executing Fileman::upload_files  using the UAPI, the following error returns:

You must specify at least one file to upload.

Description 

Due to how the temporary file is saved before saving, the user does not have access to the uploaded file.

Workaround

Authenticate as the user using the UAPI on port 2083