Sometimes failed call can't hang up.

[Android Question]

Sometimes, when I try to place a call with my Nexus 4, the call fails to go through (no audio, no ringing, just silence). In those cases, when I hit "hang up" it often ends up stuck on "hanging up" and doesn't actually hang up the call. How do I cleanly fix this problem? I've been just rebooting the phone when this happened, and it works again when it comes back up. Is this a known issue? I haven't found anything about it while googling.

This has been an occurrence for a while (not just the latest updates).

Thanks!