作曲家没有首先寻找替代的VCS / Git Repo

我的composer.json文件中包含以下内容，用于bear / package，它正在拾取替代的git repo，但是不用于bear / skeleton。对于bear / skeleton来说，它是从packagist获取主要的repo checkout da04548，而不是从github.com/mackstar帐户获取6b3bd0ae16。

有谁知道为什么这对一个仓库有效，而对另一种仓库无效？

提前致谢。

{
"name": "mackstar/spout",
"description":"A BEAR.Sunday based CMS",
"keywords":[
    "PHP",
    "CMS"
],
"authors":[
    {
        "name": "Richard McIntyre"
    }
],
"repositories": [

    {
        "type": "vcs",
        "url":  "https://github.com/mackstar/BEAR.Skeleton"
    },
    {
        "type": "vcs",
        "url":  "https://github.com/mackstar/BEAR.Package"
    }
],
"require":{
    "php":">=5.4.0",
    "ext-curl":"*",
    "bear/resource":"0.9.*",
    "bear/skeleton":"dev-develop",
    "bear/package":"dev-develop",