We have PATH set on our build slaves (via configure -> Node properties -> Environment Variables) that won't work in most docker containers.  Specifically, we use /usr/local/bin:/a/bin.  Note how /usr/bin and /bin aren't in the PATH (which is where cat usually is located.

Normally, the docker.inside() command's docker run isn't setting the -e PATH=... flag.  But every so often it uses the PATH from the build slave configuration which causes the docker run to not find cat

docker: Error response from daemon: oci runtime error: container_linux.go:247: starting container process caused "exec: \"cat\": executable file not found in $PATH".

I was able to track this down by modifying docker-workflow to not mask the PATH: https://github.com/jenkinsci/docker-workflow-plugin/pull/96

I don't know what the expected behavior (overriding the PATH on a container seems like a "Bad Idea", since the container may-or-may-not be in LSB/POSIX layout) is supposed to be.

It is clear that this random flipping between behaviors is bad.