AAR is no longer being generated with Android Plug in 3.0.0

My app is setup to build a generic main aar that is included in individual customer apps.

Previously the aar would appear at

/{library_name}/build/outputs/aar/core-release.aar

Here is the gradle file for the entire project

buildscript {
    repositories {
        jcenter()
        google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.0'
    }
}

allprojects {
    repositories {
        jcenter()

        maven {
            credentials {
                username ''
                password ''
            }

            url 'https://artifactory.*.com/artifactory/*-libs/'

        }
        google()
    }
}

Here is the gradle for the library that should be generating an aar

apply plugin: 'com.android.library'

dependencies {
    implementation project(':AndroidAsync')
    implementation project(':simplezxing')



    implementation('org.apache.httpcomponents:httpmime:4.5.1') {
        exclude module: "httpclient"
    }
    implementation 'net.danlew:android.joda:2.9.+'
    implementation 'com.squareup.picasso:picasso:2.5.2'
    implementation 'com.google.android.gms:play-services-location:9.0.2'
    implementation 'com.google.android.gms:play-services-gcm:9.0.2'
    implementation 'com.google.android.gms:play-services-maps:9.0.2'
    implementation 'com.android.support:support-v13:25.3.0'

    implementation 'com.jakewharton:butterknife:8.8.1'
    annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'

}

android {
    compileSdkVersion 21
    buildToolsVersion '26.0.2'

    defaultConfig {
        multiDexEnabled false
        minSdkVersion 18
        targetSdkVersion 21
        versionCode 1604020110 //Last two digits are build type 0 = Developer, 1 = Development, and 5 rc and 10 for release
        versionName "4.2.1"
    }

    signingConfigs {
        debug {
            storeFile file("keystores/debug.keystore")
        }

        release {
            storeFile file("keystores/*-android.keystore")
            storePassword ""
            keyAlias ""
            keyPassword ""
        }
    }

    lintOptions {
        abortOnError false
    }

    packagingOptions {
        exclude     'META-INF/DEPENDENCIES'
        exclude     'META-INF/LICENSE'
        exclude     'META-INF/LICENSE.txt'
        exclude     'META-INF/NOTICE'
        exclude     'META-INF/NOTICE.txt'
    }

    dexOptions {
        jumboMode true
        javaMaxHeapSize "4g"
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }
}

I did remove some company specific info.

The rest of my build is working fine on jenkins but the aar is just not present as expected.

edit

This builds the aar correctly when I build my jenkins by branch which uses

./gradlew clean build

If I build by product flavor it doesn't build the aar, this uses

./gradlew clean assemble{flavor}