Incoming Android Messenger calls ignore volume settings

REPRODUCIBILITY: 100%
OS VERSION: 4.5
HARDWARE: Sony Xperia 10 II Dual Sim
UI LANGUAGE: German
REGRESSION: was there bevor the last update

DESCRIPTION:

If I receive an incoming call via a Android Messeger (e.g. Telegram) the phone rings even if it is set to mute. The ring tone is the ring tone of the app and not the ring tone set for the ambience.

PRECONDITIONS:

WhatsApp or Threema or Telegram account is required.

STEPS TO REPRODUCE:

  1. Put your phone on mute or a vibrate only ambience
  2. Receive a call via a Messenger

EXPECTED RESULT:

No rining.

ACTUAL RESULT:

Phone rings with ringtone. Standard Android (?)

MODIFICATIONS:

none

ADDITIONAL INFORMATION:

If you tell me how, I am happy to provide logs etc.

Thanks for looking into this