I created a material function to fade materials to black if the player is far away from them. I am making a horror game, so his view distance must be limited and dark.

The material fades to black when far away on PC, but it stays orange when launching on my mobile phone (s9 plus). I have a feeling it has something to do with the absoluteworldposition and/or camera position, but I am not sure.
Waiting for some input…thanks
Materials that you use for mobile do not have all functions like materials for a pc game.
Did you already read this: Materials for Mobile Platforms | Unreal Engine Documentation
Maybe this video can help u 2: Depth & Location Based Effects | Live Training | Unreal Engine - YouTube
I really hope this solves your problem.
So, my conclusion (correct me if I am wrong) is that I need to enable full precision for mobile on the texture. However, if I do that, it won’t be supported on a lot of devices, and this effect is absolutely critical for me game. So I will have to use something else to get this effect.
The only alternative I can think of is height fog, but it doesn’t give me the effect I am looking for.