[Pixel 4a / CalyxOS 5.17.1] Call echo: other party hears their own voice during phone and Signal calls

Basic info

• Device: Pixel 4a sunfish
• CalyxOS version: 5.17.1

Brief description of the issue

After updating to CalyxOS 5.17.1 on my Pixel 4a (sunfish), callers report hearing their own voice echoed back during both regular phone calls and Signal calls. This issue started after the 5.17.1 update and is 100% reproducible.

Steps to reproduce

1. Use Pixel 4a (sunfish) running CalyxOS 5.17.1.
2. Initiate or receive a regular phone call or Signal call using the earpiece (not speaker or headphones).
3. Ask the other person if they hear their own voice.

Expected result

• No echo for the other party during calls.

Actual result

• Other person hears loud echo of their own voice.