IDK if it helps, but I had similar behaviour last week. Ring tone (was set to default Nokia) just rang once and then there was silence.
I had upgraded after restoring from a backup. And I found that it was something with package tweakr and its profile presets. When changing loudness in settings directly, it just rang once and silence. After having selected the profile via tweakr everything was/is fine.
Maybe it helps to find out ...