given the following pipeline, I would expect the "with NO agent" stage to trigger without any agent being launched. This is not the case, all stages are launched with an agent. This is specially a problem when I have an "input" step waiting for a user interaction in one of the stages defined.

pipeline {
    agent any
    tools {
        jdk "Oracle JDK 1.8 (latest)"
    }    
    stages {
        stage ('with any agent 0') {
            steps 
                sh "java -version"
            }
        }  
        stage ('with NO agent') {
            agent none
            steps {
                sh "java -version"
            }
        }
        stage ('with any agent 1') {
            steps {
                sh "java -version"
            }
        }        
    }
}

This is also the case where "with NO agent" is the first stage in the pipeline.

btw. I was only able to discover this because of JENKINS-42338 - I think it would also be a good idea to have the "stage" step print some info on which agent it actually runs.