I wasn't sure if i should go to the gzdoom site or not, but it seemed right coming here first being your project. I'm also not sure if you're aware of this yet but i will show you. In tnt map 2 here is a shot with normal textures, sorry for the file size.



And here is the same shot with hi-res textures enabled



What is happening here?

the switch texture is missing from the tnt part of the pack, and as a result gzdoom is using the texture from another part of the pack that has the same name as the missing tnt texture