Enabling R8 crashes application

So I enabled R8 in my project by adding android.enableR8=true to gradle.properties. This is my gradle file:

buildTypes {
        release {
            useProguard false
            minifyEnabled true
            debuggable false
            multiDexEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.release
        }
...

But when I run a build, I got this crash when app launches:

java.lang.RuntimeException: Unable to instantiate application com.example.application.MyApplication: java.lang.NullPointerException: throw with null exception
        at android.app.LoadedApk.makeApplication(LoadedApk.java:1069)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:5842)
        at android.app.ActivityThread.access$1100(ActivityThread.java:199)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1650)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.NullPointerException: throw with null exception
        at com.example.application.MyApplication.<init>(MyApplication.kt:18)
        at java.lang.Class.newInstance(Native Method)
        at android.app.AppComponentFactory.instantiateApplication(AppComponentFactory.java:50)
        at androidx.core.app.CoreComponentFactory.instantiateApplication(CoreComponentFactory.java:52)
        at android.app.Instrumentation.newApplication(Instrumentation.java:1120)
        at android.app.LoadedApk.makeApplication(LoadedApk.java:1061)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:5842) 
        at android.app.ActivityThread.access$1100(ActivityThread.java:199) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1650) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 

I added those on my proguard file, so R8 don't remove or obfuscate anything

-dontobfuscate
-dontshrink
-dontoptimize

and the app still crashes.

I tried to migrate to Proguard by setting android.enableR8=false to gradle.properties and useProguard true in Gradle file, and the app worked fine without crashing.

Did anyone encounter the same issue?

Btw, my project is in Kotlin.