iPhone 8 (iOS 11.2.6) sound crackling/popping in third party apps

Hi!

I'm facing strange sounds (crack/pop) quite often while working with some third party applications:

1. YouTube

2. Night Sky

3. Tiles

Sounds like some kind of distortion.

Same applications work fine on the older iPhone device (SE iOS 10).

But if I use Bluetooth headset - the sound is perfect.

Seems like speakers are fine too, because if I just listen to a song or watch a clip without any switching - I don't hear distortions, the sound is loud and good. Maybe the are some issues in software-hardware compatability on new models, because I've never experinced such problems with previous one.

How this starnge sounds can be explained? Is there any hope for fix in upcomming iOS updates > 11.2.6?