Is there an issue connecting to GitHub from the AV build machines?

We're getting sporadic ECONNRESET errors when running npm install grunt-contrib-imagemin. I've setup a reproducable example yml file as follows using pngquant-bin, a dependency of grunt-contrib-imagemin:

version: 1.0.{build}
install:
- ps: Install-Product node 0
build_script:
- node --version
- npm --version
- npm install grunt pngquant-bin

The vast majority of the time, we get ECONNRESETs when the installer downloads binaries from github (see the line with ‼ read ECONNRESET:

Build started
git clone -q --branch=master https://bitbucket.org/livsmarter/av-build-problem.git C:\projects\av-build-problem
git checkout -qf f1efe686b3d060a7a624b0b2196b21b5d97bd9f3
Running Install scripts
Install-Product node 0
Uninstalling node 0.10.38 (x86)... 
Installing node 0.12.2 (x86)... 
node --version
v0.12.2
npm --version
2.7.4
npm install grunt pngquant-bin




> pngquant-bin@2.0.3 postinstall C:\projects\av-build-problem\node_modules\pngquant-bin
> node lib/install.js




‼ read ECONNRESET 
  ‼ pngquant pre-build test failed
  i compiling from source
  × Error: pngquant failed to build, make sure that libpng-dev is installed
    at ChildProcess.exithandler (child_process.js:751:12)
    at ChildProcess.emit (events.js:110:17)
    at maybeClose (child_process.js:1015:16)
    at Process.ChildProcess._handle.onexit (child_process.js:1087:5) 
grunt@0.4.5 node_modules\grunt
├── dateformat@1.0.2-1.2.3
├── which@1.0.9
├── eventemitter2@0.4.14
├── getobject@0.1.0
├── colors@0.6.2
├── rimraf@2.2.8
├── async@0.1.22
├── grunt-legacy-util@0.2.0
├── hooker@0.2.3
├── exit@0.1.2
├── nopt@1.0.10 (abbrev@1.0.5)
├── minimatch@0.2.14 (sigmund@1.0.0, lru-cache@2.5.0)
├── glob@3.1.21 (inherits@1.0.0, graceful-fs@1.2.3)
├── lodash@0.9.2
├── coffee-script@1.3.3
├── underscore.string@2.2.1
├── iconv-lite@0.2.11
├── findup-sync@0.1.3 (glob@3.2.11, lodash@2.4.1)
├── grunt-legacy-log@0.1.1 (underscore.string@2.3.3, lodash@2.4.1)
└── js-yaml@2.0.5 (argparse@0.1.16, esprima@1.0.4)




pngquant-bin@2.0.3 node_modules\pngquant-bin
├── logalot@2.1.0 (figures@1.3.5, squeak@1.2.0)
├── bin-build@2.1.1 (exec-series@1.0.1, url-regex@2.1.2, tempfile@1.1.0, archive-type@2.0.0, rimraf@2.3.2, decompress@2.2.1, download@3.3.0)
└── bin-wrapper@2.1.3 (os-filter-obj@1.0.3, is-path-global@1.0.1, download-status@2.1.1, npm-installed@1.0.0, bin-check@1.0.0, bin-version-check@2.1.0, globby@1.2.0, lnfs@1.0.0, download@3.3.0)
dir node_modules\pngquant-bin\vendor
 Volume in drive C has no label.
 Volume Serial Number is F074-BCDF




Directory of C:\projects\av-build-problem\node_modules\pngquant-bin




File Not Found
Command exited with code 1

During the postinstall script, npm tries to download a file from github, specifically https://raw.githubusercontent.com/imagemin/pngquant-bin/v2.0.3/vend... and it looks like this is where the ECONNRESET happens. Checking the contents of C:\projects\av-build-problem\node_modules\pngquant-bin\vendor verifies this.

Interestingly (or frustratingly), it works some of the time:

Build started
git clone -q --branch=master https://bitbucket.org/livsmarter/av-build-problem.git C:\projects\av-build-problem
git checkout -qf f1efe686b3d0
Running Install scripts
Install-Product node 0
Uninstalling node 0.10.38 (x86)... 
Installing node 0.12.2 (x86)... 
node --version
v0.12.2
npm --version
2.7.4
npm install grunt pngquant-bin




> pngquant-bin@2.0.3 postinstall C:\projects\av-build-problem\node_modules\pngquant-bin
> node lib/install.js




√ pngquant pre-build test passed successfully 
grunt@0.4.5 node_modules\grunt
├── dateformat@1.0.2-1.2.3
├── which@1.0.9
├── getobject@0.1.0
├── eventemitter2@0.4.14
├── colors@0.6.2
├── rimraf@2.2.8
├── async@0.1.22
├── grunt-legacy-util@0.2.0
├── hooker@0.2.3
├── exit@0.1.2
├── nopt@1.0.10 (abbrev@1.0.5)
├── minimatch@0.2.14 (sigmund@1.0.0, lru-cache@2.5.0)
├── glob@3.1.21 (inherits@1.0.0, graceful-fs@1.2.3)
├── lodash@0.9.2
├── coffee-script@1.3.3
├── underscore.string@2.2.1
├── iconv-lite@0.2.11
├── grunt-legacy-log@0.1.1 (underscore.string@2.3.3, lodash@2.4.1)
├── findup-sync@0.1.3 (glob@3.2.11, lodash@2.4.1)
└── js-yaml@2.0.5 (argparse@0.1.16, esprima@1.0.4)




pngquant-bin@2.0.3 node_modules\pngquant-bin
├── logalot@2.1.0 (figures@1.3.5, squeak@1.2.0)
├── bin-build@2.1.1 (exec-series@1.0.1, url-regex@2.1.2, tempfile@1.1.0, archive-type@2.0.0, rimraf@2.3.2, decompress@2.2.1, download@3.3.0)
└── bin-wrapper@2.1.3 (os-filter-obj@1.0.3, is-path-global@1.0.1, download-status@2.1.1, npm-installed@1.0.0, bin-check@1.0.0, bin-version-check@2.1.0, globby@1.2.0, lnfs@1.0.0, download@3.3.0)
dir node_modules\pngquant-bin\vendor
 Volume in drive C has no label.
 Volume Serial Number is F074-BCDF




Directory of C:\projects\av-build-problem\node_modules\pngquant-bin\vendor




04/07/2015  02:58 PM    <DIR>          . 
04/07/2015  02:58 PM    <DIR>          .. 
04/07/2015  02:58 PM           544,355 pngquant.exe
               1 File(s)        544,355 bytes
               2 Dir(s)  56,997,486,592 bytes free
Discovering tests...OK
Build success

I've been able to reproduce the issue with optipng-bin, gifsicle, jpegtran-bin and grunt-contrib-imagemin which is what we use on our main build and is causing us constant build failures since it has dependencies on the other 4 packages I've mentioned.