The editor is a very simple application. It only alters the file when you save. The game loads the file from the disk, meaning if it shows up ingame, then you saved the file and the editor is done. The editor is too simple to be able to save old versions of the file meaning it can't revert tga files. The fact that ignoring the launcher fixes the problem strongly indicates that the problem is the launcher and not the editor. You need to look into what that launcher does.