This issue affects both Heretic and Hexen. Text screens between episodes or hubs are cut off at the end, the amount depending on the screen resolution. The above screenshot is taken at 1920x1080, it's even worse in some resolutions like 320x200. The problem seems to be that Heretic and Hexen used little spacing between lines, but Doom used more, and it seems to be using Doom's value for drawing the screens.