I regularly use Apple Carplay in my 2019 Leaf, with an iPhone 8. The sound is typically fine for playing music and podcasts, but not so for other functions like IM and phone calls. Often the sound quality for phone calls and for trying to send/listen to text messages is so bad (broken up and otherwise very staticky) as to make those features effectively unusable. I've tried different lightning cables, which hasn't helped.
Has anyone else experienced this and if so were you able to fix the problem?