job-restrictions-plugin does not support Pipeline Plugin (aka Workflow plugin) and it's behavior is not as expected.
Steps to reproduce it:
Create a job using Pipeline Plugin (https://wiki.jenkins-ci.org/display/JENKINS/Pipeline+Plugin)
Create a slave in your master called for example 'demo-slave'.
In your Groovy script using pipeline do:
After in 'demo-slave' configuration, restrict it:
No matter if you start your job with 'daniel_hernandez' user or other user, the job will not get a executor from the demo-slave node getting the message:
Waiting for next available executor on demo-slave
After, You can release it setting the value to 'Take any job'