serverless-webpack: Single function deploy does not invoke the plugin

I do not know if this is a problem with Serverless’ lifecycle events or if it is a problem within the webpack plugin. If I try to upload a single function during development, using serverless deploy function -f auth the webpack build is not triggered and Serverless tries to upload the whole project which exceeds the upload file size limit of 70MB.

When deploying the complete service with serverless deploy the plugin is invoked correctly and the resulting function code ZIP is about 17MB.

Serverless: Deploying function: auth...
Serverless: Packaging function: auth...
Serverless: Uploading function: auth (90.02 MB)...

  Serverless Error ---------------------------------------

     Request must be smaller than 69905067 bytes for the
     UpdateFunctionCode operation

  Get Support --------------------------------------------
     Docs:          docs.serverless.com
     Bugs:          github.com/serverless/serverless/issues

  Your Environment Information -----------------------------
     OS:                 win32
     Node Version:       4.3.1
     Serverless Version: 1.6.1

If it turns out that the problem is on Serverless’ side, we should create an issue there.