On a multi-configuration job, the PATH env var is being over written by the PATH var of the parent node.

Steps to Reproduce:
1) Create a multi-configuration job
2) Set the axis on Slaves (choose 2 different OS slave so that you can clearly see the problem)
3) As a build step select "Execute Shell" and simply type "env | sort", so that you can see the environment.
3) DO NOT SELECT "Prepare an environment for the job"
Build the project and notice PATH is correct, depending on which slave it ran on. (Windows slave have their path correct, and non-windows have their path correct)
4) Now select "Prepare an environment for the job" and check:
Keep Jenkins Environment Variables
Keep Jenkins Build Variables
Load files from the master (create some dummy file on the master, just to exercise this plugin)

Now build the project, and notice that both slaves are inheriting the same PATH env from the master. This breaks all jobs running on Slaves.

This is using the latest EnvInject plugin, 1.35

If you need more info, let me know!