I think I got the problem, but for me it occurs only in the first registration. The UPS is sending a message after registration with the registrationId

Bundle[

    {

        org.jboss.aerogear.android.unifiedpush.MESSAGE=true,

        registration_id=APA91bEnPMvUsWYQ3iCUbjOx2Fp5Wc49uBucBqU3LvIo3SqvOwG_votXKy0J4C2YvmYnMoj9D0SStibAEd1sHPZedHQLZrWF68-Ck5z3rtgY8GMV7FwWqepybKrTJ_Wm53wZACIziIIyXyDEzgpqdMpxjSejvzWSvZawKI840jLb13U2pKkGJR8

    }

]

So, the app will show the notification with a null message and when you click on notification the app is trying send a metrics but the messageId was not received causing an exception.

1. Receive a message after registration is new for me and I have no idea why we need it (in Android land)
2. This message is coming why a key MESSAGE=true so I can't filter using it

To solve it i'm adding an ugly if in application testing if the message is not null.