no sound via mobile network call
There seems to be a pretty bad bug that affects Cyanogenmod right now

https://jira.cyanogenmod.org/browse/CYAN-5728

A workaround provided in the thread:

from a root terminal (adb root/adb shell or terminal emulator/su)

pm disable com.google.android.gms/com.google.android.gms.checkin.CheckinService