Yes i experienced this in most of the voip apps - not gsm calls -on all custom roms since android 9 on shamu . No fix i gess.Really loving this ROM on my old Nexus 6 because everything I'm using works (especially Google Family LInk).
The one issue I'm experiencing is when using speakerphone, the caller hears an annoying echo on their end. Anybody know a fix for this?