Packagist: "create-project" from fork loads original repo

I'm just trying to grasp the concepts of dependency managers and GIT systems, so it's very possible I'm missing something very basic.

I use ROOTS/BEDROCK project as a base of my Wordpress projects. It allows to use Composer with Wordpress (by adding Wordpress itself as a dependency) and various other awesome features. It is installable as a Packagist package by command composer create-project roots/bedrock.

However to make it fit with my Wordpress framework, I needed to do a light customization of the project. So I forked it and submited the fork to http://packagist.org with entirely new composer.json file.

What I do not understand is why composer after command composer create-project myaccount/forked_bedrock installs original repository and not my fork.

TL;DR

Is it possible to submit a forked GitHub repository to Packagist and use the fork (not the original repo) by create-project command?

Thanks in advance!

It seems that the problem lied within Composer cache - after I've cleared it, Composer loaded the forked GitHub repository (not the original).

If Composer caches so "heavily", it would be nice if there was some option to clear/flush the cache, but apparently there is nothing built-in ...