I was going to ask about the deprecation notice I have been getting from composer but I found a solution.
The notice was:
Deprecation Notice: Composer\Package\Version\VersionParser::parseLinks is deprecated. Use \Composer\Package\Loader\ArrayLoader::parseLinks() instead in phar:///usr/local/bin/composer/src/Composer/Package/Version/VersionParser.php:226
I found the solution by reading some open issues in the yii2 project. In the end all I had to do was update the composer asset plugin like so:
composer global require "fxp/composer-asset-plugin:~1.0.3"
I had version 1.0.0 installed from my original installation of yii2 advanced template.
I hope this helps someone, this was driving me crazy.