Admob causes NullPointerException in android apps

Since last week i'm getting a fatal error in my app in production release due some admob bug

Fatal Exception: java.lang.NullPointerException: Attempt to read from field 'com.google.android.gms.ads.internal.overlay.n com.google.android.gms.ads.internal.overlay.AdOverlayInfoParcel.c' on a null object reference
       at com.google.android.gms.ads.internal.overlay.k.f(k.java)
       at com.google.android.gms.ads.internal.overlay.client.b.a(b.java:1)
       at fy.onTransact(fy.java:4)
       at android.os.Binder.transact(Binder.java:662)
       at com.google.android.gms.internal.ads.zzgu.zzb(zzgu.java:21)
       at com.google.android.gms.internal.ads.zzarl.onUserLeaveHint(zzarl.java:54)
       at com.google.android.gms.ads.AdActivity.onUserLeaveHint(AdActivity.java:32)
       at android.app.Activity.performUserLeaving(Activity.java:7470)
       at android.app.Instrumentation.callActivityOnUserLeaving(Instrumentation.java:1476)
       at android.app.ActivityThread.performUserLeavingActivity(ActivityThread.java:4034)
       at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:4016)
       at android.app.servertransaction.PauseActivityItem.execute(PauseActivityItem.java:45)
       at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:145)
       at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1839)
       at android.os.Handler.dispatchMessage(Handler.java:106)
       at android.os.Looper.loop(Looper.java:201)
       at android.app.ActivityThread.main(ActivityThread.java:6864)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)

I was not able to reproduce the problem in test. but as the stack shows it is caused due some inner call of the admob api responding to android native events.

the versions i'm using:

'com.google.gms:google-services:4.3.4'
api "com.google.android.gms:play-services-location:17.1.0"
api 'com.google.android.gms:play-services-ads:19.5.0'

from Admob causes NullPointerException in android apps