Estoy usando la versión de Android Studio

Android Studio 3.2 Canary 14
Build #AI-181.4668.68.32.4763614, built on May 4, 2018
JRE: 1.8.0_152-release-1136-b02 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Mac OS X 10.11.6

Mientras investigaba los nuevos componentes de navegación arquitectónica android.arch.navigation, encontré este error de compilación.

AGPBI: {"kind":"error","text":"Program type already present: android.support.v4.os.ResultReceiver$1","sources":[{}],"tool":"D8"}
:app:transformDexArchiveWithExternalLibsDexMergerForDebug FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:transformDexArchiveWithExternalLibsDexMergerForDebug'.
> com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: ...
...
  Program type already present: android.support.v4.os.ResultReceiver$1

La compilación de mi aplicación gradle se parece a: -

apply plugin: 'com.android.application'
apply plugin: "androidx.navigation.safeargs"

android {
    compileSdkVersion 'android-P'
    defaultConfig {
        applicationId "com.research.frager"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    def nav_version = "1.0.0-alpha01"

    implementation "android.arch.navigation:navigation-fragment:$nav_version"
    implementation "android.arch.navigation:navigation-ui:$nav_version"

    // optional - Test helpers
    androidTestImplementation "android.arch.navigation:navigation-testing:$nav_version"

    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.0.0-alpha1'

    implementation 'androidx.constraintlayout:constraintlayout:1.1.0'
    implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0-alpha1'
    testImplementation 'junit:junit:4.12'

    androidTestImplementation 'androidx.test:runner:1.1.0-alpha2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0-alpha2'
}

y construcción de gradle a nivel de proyecto: -

buildscript {

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.2.0-alpha14'
        classpath "android.arch.navigation:navigation-safe-args-gradle-plugin:1.0.0-alpha01"
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

He intentado refactorizar a AndroidX, pero recibo un mensaje que indica que no se encontraron usos en el proyecto, entonces, ¿por qué todavía se menciona esta clase "v4"?