Voice Call -Speaker- Phase difference between two speakers

[scrutinizer80]

• I have searched open and closed issues for duplicates
• I am submitting a bug report for existing functionality that does not work as intended
• This isn't a feature request or a discussion topic

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Bug description

When having a voice call using the loudspeaker, the audio gets routed to both the loudspeaker and the ear-speaker at once, creating an unfocused "stereo-like" effect due to a lack of synchronization between the two, resulting in a slight phase shift.

Steps to reproduce

Start a voice call with anyone & press the loudspeaker button.

Actual result:
Call works fine, but audio is being played from both the loudspeaker and the ear-speaker at the same time, with a phase shift between them resulting in a stereo-like effect.

Expected result:
When pressing the loudspeaker button, Audio should be played from the loudspeaker only or be in complete synchronization with the ear-speaker - as it does in cellular calls.

Device info

Device: iPhone 7 Plus
iOS version: 15.8.2
Signal version: 7.15