Custom pixi build doesn't exclude modules and still creates full lib?

[Tweeper]

Hi, I'm trying to do a custom build of the pixi lib to optimize the filesize of the lib in a project. But for some reason it keeps on building the full lib (all modules), even though I have the -e or --exclude parameters added.

This is what I did so far (following the instructions on the Pixi Github page):
* downloading and unzipping the full pixi zip file (v4.2.2)
* in the root of the pixi folder: npm install (creating node modules folder)
* in the root of the pixi folder: npm run build -- -e extras -e interaction -e filters  (also tried: npm run build -- --exclude extras --exclude interaction --exclude filters)

For some reason this keeps on building the full pixi and minimize pixi files in the dist-folder, so it didn't exclude the modules mentioned.

I am trying to debug this at the moment, but I'm not very familiar with npm and so far I'm a little in the dark. I upgraded nodeJs to version 6.9.1 some days ago, so that should be ok.
Am I missing something here?