Do you want to request a feature or report a bug?
Bug

What is the current behavior?
When installing certain packages the yarn.lock file is changed. It seems to be package specific. In this case cordova triggers the behavior.

If the current behavior is a bug, please provide the steps to reproduce.

In an empty directory, do the following:

yarn init
yarn add cordova
cp yarn.lock yarn.lock.initial
rm -r node_modules
yarn install
diff yarn.lock.initial yarn.lock

Notice that the yarn.lock file has changed.

What is the expected behavior?

Installing should not change the lock file if it already exists.

Please mention your node.js, yarn and operating system version.

node v6.11.3, yarn v1.0.1, Mac OS 10.11.6