artifactoryPublish would not deploy pom file along with jars when using pipeline code. 

It works fine when running the tasks from command line and Jenkins gradle plugin from Freestyle project.

stage("Build") {
env.JAVA_HOME="${tool 'Java8'}"
env.PATH="${env.JAVA_HOME}/bin:${env.PATH}"
withEnv(["GRADLE_USER_HOME=$\{env.WORKSPACE}"]){

def server = Artifactory.server SERVER_ID
def rtGradle = Artifactory.newGradleBuild()
rtGradle.deployer.deployMavenDescriptors = true
rtGradle.deployer.mavenCompatible = true
rtGradle.deployer.deployIvyDescriptors = true
rtGradle.tool = "gradle-4.0"
rtGradle.deployer repo: "jncs-snapshot-local", server: server

def buildInfo = Artifactory.newBuildInfo()
buildInfo.env.capture = true
buildInfo.env.filter.addInclude("*")

rtGradle.usesPlugin = true
rtGradle.run rootDir: "jncs-core", buildFile: "build.gradle", tasks: "clean build artifactoryPublish" , buildInfo: buildInfo

server.publishBuildInfo buildInfo

}
}