I’m actively working on finding a solution to this problem as well.

I’ve tried both the AVAudioEngine installTap method and the lower-level AudioUnit API, but so far, there’s no difference.

Interestingly, the issue doesn’t occur on the iPhone 12, but it does on the iPhone 16 Pro Max, even though both are running iOS 18.

I’ll keep experimenting and will update this post if I discover anything.