deploy command not picking up deploy.env variables

Start with the deploy command in package.json, deploy.env, and the credential-related code around lib/main.js lines 700-701. Trace how --configFile values and other node-lambda CLI parameters reach the AWS request, then verify deployment with the reported configuration succeeds without the invalid-token error.

In my package.json I have the following deploy command in scripts:

  "scripts": {
    "deploy": "node-lambda deploy --configFile deploy.env --prebuiltDirectory dist",

My deploy.env is:

AWS_ACCESS_KEY_ID=xxx
AWS_SECRET_ACCESS_KEY=yyy

If I log the key and secret key here I get this:

your_key your_secret

followed by this error:

The security token included in the request is invalid.

UnrecognizedClientException: The security token included in the request is invalid.
    at Object.extractError (MY_PROJECT\node_modules\aws-sdk\lib\protocol\json.js:48:27)
    at Request.extractError (MY_PROJECT\node_modules\aws-sdk\lib\protocol\rest_json.js:37:8)
    at Request.callListeners (MY_PROJECT\node_modules\aws-sdk\lib\sequential_executor.js:105:20)
    at Request.emit (MY_PROJECT\node_modules\aws-sdk\lib\sequential_executor.js:77:10)
    at Request.emit (MY_PROJECT\node_modules\aws-sdk\lib\request.js:678:14)
    at Request.transition (MY_PROJECT\node_modules\aws-sdk\lib\request.js:22:10)
    at AcceptorStateMachine.runTo (MY_PROJECT\node_modules\aws-sdk\lib\state_machine.js:14:12)
    at MY_PROJECT\node_modules\aws-sdk\lib\state_machine.js:26:10
    at Request.<anonymous> (MY_PROJECT\node_modules\aws-sdk\lib\request.js:38:9)
    at Request.<anonymous> (MY_PROJECT\node_modules\aws-sdk\lib\request.js:680:12)

I'm not sure what the problem is here. Can I not use a combination of --configFile and other node-lambda CLI parameters?

The env vars are in the params if I print those out:

params { FunctionName: 'MY_FUNCTION_NAME',
  Code: { ZipFile: <Buffer 50 4b 03 04 0a 00 00 00 08 00 49 58 bd 4a 9e b6 b4 2d 70 ff 07 00 81 ac 24 00 08 00 00 00 69 6e 64 65 78 2e 6a 73 ec bd 7b 7b 1b 37 ae 38 fc 7f 9e e7 ... > },
  Handler: 'index.handler',
  Role: 'your_amazon_role',
  Runtime: 'nodejs6.10',
  Description: '',
  MemorySize: '128',
  Timeout: '3',
  Publish: false,
  VpcConfig: { SubnetIds: [], SecurityGroupIds: [] },
  Environment:
   { Variables:
      { AWS_ACCESS_KEY_ID: 'xxx',
        AWS_SECRET_ACCESS_KEY: 'yyy' } },
  DeadLetterConfig: { TargetArn: null },
  TracingConfig: { Mode: null } }