ES3.1 not supporting SM5 because of custom shader

Hello everyone,

I’m new here and I have been using Unreal for a while now. I have been developing a game for Android and IOS and everytime I use the Vulkan, ES3.1 or IOS preview in the viewport, I have this weird graphical glitch.

I currently use the 4.25 version of Unreal, directly from the Source Codes. I checked everything and I have all the Android requirement (all perfectly installed in the engine too) as well as the right Visual Studio version installed. Everything worked perfectly with the engine except for the Android and IOS previews.

Now, I did check on the Epic Game Store version of Unreal 4.25 as well, and I get the same problem.

I think it might be the custom shaders I made, since I opened another project of mine that doesnt use them and everything works perfectly fine.

I tried everything and I don’t really know what is happening. Is there anything I can do for my customer cel shaders to work on mobile? Or can anybody tell me what is actually happening, so that I can learn something from that too?

Thanks a lot in advance guys.