Broken call indication (sound nor ui)

REPRODUCIBILITY: once a day
OS VERSION: 4.2.0.19
HARDWARE: Xperia 10 II
UI LANGUAGE: cs
REGRESSION: probably not, similar issues was reported by multiple ppl with 4.1

DESCRIPTION:

Sorry if this report is duplicate, I know that multiple ppl was reporting calling issues on 10 II, but the symptoms were different a bit.

Multiple times per week, people reporting me that I am not answering their calls. But I had no missed call notification and phone was not ringing that time.

PRECONDITIONS:

Just use phone.

STEPS TO REPRODUCE:

  1. call to phone with SFOS
  2. wait

EXPECTED RESULT:

phone is ringing

ACTUAL RESULT:

nothing visible in ui

ADDITIONAL INFORMATION:

ofono logs

ofono logs from this broken state when I was calling from different phone: ownCloud