I'm receiving just about the same Error when I try to register my device to GCM:
java.lang.IllegalArgumentException: Service Intent must be explicit: Intent { act=com.google.android.c2dm.intent.REGISTER (has extras) }
This is running in a service that registers and receives Push content.
The code is working nicely when I have set android:targetSdkVersion to 19 instead of 21.
I updated my SDK to latest 5.0.1 (API 21) Rev 2 today but still the same.
I´m running the app on a Note 3 with CM12 Android 5.0.2.
Any ideas?
I would like to add Material Design to my app, but not to the cost of push content...