When I install phantomjs-prebuilt v2.1.7 the contents of location.js are as follows:
module.exports.location = "phantom/bin/phantomjs"
module.exports.platform = "linux"
module.exports.arch = "x64"

When I install phantomjs-prebuilt v2.1.8 the contents of location.js change to:
module.exports.location = "/tmp/deployment/application/node_modules/phantomjs-prebuilt/lib/phantom/bin/phantomjs"
module.exports.platform = "linux"
module.exports.arch = "x64"

Now AFAIK the way Amazon Elastic Beanstalk deploys work is that once a deploy is complete it copies the contents of /tmp/deployment/application to it's proper final location and wipes the /tmp directory, so the location that location.js is pointing to no longer exists. Why would the location in location.js have changed between v2.1.7 and v2.1.8?