Voice call stutter/crackling Whatsapp on receiving end

[Android Central Question]

Whenever I try to call someone over Whatsapp (both on WiFi and LTE with good quality network) the receiver can not hear me well due to extreme stutter/crackling. It is not an issue when performing a normal phone call and the microphone quality when recording is completely fine.

I use a Galaxy S6 with LineageOS (latest version: 2019-01-26). It was already a problem when I used the default Samsung OS.

Any ideas what can cause this and if it can be solved?