Nexus 4 does not ring for calls on google talk or viper when screen is locked Nexus 4 does not ring for calls on google talk or viper when screen is locked. Directly when the screen is unlocked, I see the caller calling, even if he already long time ago stopped ringing!

The Nexus 4 is running 4.2.2.
So after some search and posting on some other forums, it turns out that it is a bug.
I'm quoting here from  Rizy7 @ Android central forums:

"Known problem with Nexus 4 WiFi.. Google have been made aware but nothing has happened so far.. Hopefully in the next update it will be fixed. To get around the problem you either need to get a new router, set a static arp on your router or you need to change some system files which means you need a rooted device."

Source : http://forums.androidcentral.com/google-nexus-4/267885-nexus4-wont-ring-when-calling-google-talk-screen-locked.html#post2699201