Bug report - Strange bug on some mobile devices

Hello, I am working on a mobile game for android devices. First problem are shaders. I have Samsung Galaxy J5 2016 and it works great but my friend have Huawei p30 lite and his map is weirdly colourful. I tried to package it ETC1, ETC2 but same result. I have asked on Reddit ue4 group, Facebook, Fiverr… How is it possible that no one seems to have answers? So that is why I marked this as a bug report.

Second problem is lighting. This is not a part of a bug report. This is just my lack of knowledge on this subject. I tried to add simple lighting to the map. (Point light, spotlight) Then I tried to build lighting and it just brakes… You can see it in the pictures: Lighting problem - UE4 - Album on Imgur How can I fix these errors? Thanks, guys.