Question Artifacts in enclosed objects

Hello.

I am making fps where you can walk on a spaceship while it is maneuvering. I have encountered a problem, you can watch the problem in this video (link), when I am inside an isolated structure while it is rotating shadows are 'flickering' and, if you look at the gun in the lower left part of the view, you can see colors changing on the surface, although all visible lights around the gun in question are static relative to the gun, colors on the surface correspond to the color of the sky that the surface is facing. To research this problem I have hidden all the light types in the Debug UI and turned off sky reflections on the active camera, to my surprise the surface still got it's color updated, like in the attached gif.



I have played with the debug ui and hdrp settings to no avail. I use HDRI sky, the only way to remove the color change is to set Intensity mode to Multiplier and Multiplier itself to 0. This removes the glimmer, but this is not a solution, since it makes the sky black. So my question can be split like this:

1. How to deal with the 'glimmer', if it's possible?
   
2. How to deal with shadows 'twitching', if it's possible?

I am a bit lost at how to approach this, so any help is appreciated. I use default settings with added tonemapping.

Thanks for your time!

 

It turned out that the glimmer is actually the reflection of the skybox. A workaround the problem 1 is to disable Sky Reflection in Project Settings > HDRP Default Settings > Default frame settings for Camera > Lighting or in camera's custom frame settings. This workaround removes sky reflections everywhere, even while outside enclosed objects, so it is not a perfect solution. After a day of tinkering with the settings problem 2 remains open though.

 

You need reflections probe that covers your enclosed rooms, otherwise you will not get a perfect pitch black room.
Sky reflection and ambient affect everything if you do not place override probes.