Thousands of strange crashes in new Google Play Console version

The ANRs & crashes section of the Google Play Console has been recently updated to display more ANRs & crashes (automatically collected from users that have opted in).

I found a lot of strange new crashes, on various Android versions and devices:

1) The most common (thousands of occurrences a week), a ClassNotFoundException without any class name:

java.lang.RuntimeException: 
    at android.app.LoadedApk.makeApplication(LoadedApk.java:509)
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4657)
    at android.app.ActivityThread.access$1400(ActivityThread.java:159)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1376)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:176)
    at android.app.ActivityThread.main(ActivityThread.java:5419)
    at java.lang.reflect.Method.invokeNative(Method.java:0)
    at java.lang.reflect.Method.invoke(Method.java:525)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
    at dalvik.system.NativeStart.main(NativeStart.java:0)
Caused by: java.lang.ClassNotFoundException: 
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:64)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
    at android.app.Instrumentation.newApplication(Instrumentation.java:992)
    at android.app.LoadedApk.makeApplication(LoadedApk.java:504)

2) The most common (hundreds), a RuntimeException that seems related to admob (com.google.android.gms.ads.internal.*):

java.lang.RuntimeException: 
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2377)
  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2429)
  at android.app.ActivityThread.access$800(ActivityThread.java:151)
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1342)
  at android.os.Handler.dispatchMessage(Handler.java:110)
  at android.os.Looper.loop(Looper.java:193)
  at android.app.ActivityThread.main(ActivityThread.java:5333)
  at java.lang.reflect.Method.invokeNative(Method.java:0)
  at java.lang.reflect.Method.invoke(Method.java:515)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644)
  at dalvik.system.NativeStart.main(NativeStart.java:0)
Caused by: java.lang.IllegalStateException: 
  at com.google.android.gms.ads.internal.zzj.a(zzj.java:322)
  at com.google.android.gms.ads.internal.client.ak.onTransact(ak.java:98)
  at android.os.Binder.transact(Binder.java:361)
  at com.google.android.gms.internal.zzet$zza$zza.zza(zzet.java:0)
  at <OR>.zza(zzet.java:0)
  at <OR>.zza(zzet.java:0)
 ...
  at <OR>.zza(zzet.java:0)
  ...

Notes:

• the stack trace is very long and contains a lot of methods with , line number is always 0

• the app uses Proguard

• lib folder architecture

3) a bunch of other exceptions with same kind of traces (a lot of methods with and line number 0)

My questions are:

• Do you experience similar reports?
• Are these reports really relevant? I mean, I should receive more direct user feedbacks. Is it possible, they are "silent" crashes?
• Are there any know issues / fixes?