I've played episodes 2 and 3 of Heretic with additional textures/models/music, without problems.
But in e4m1 at the location pointed in the map (see first screenshot), when the platform rises, instead of showing the floor texture and allowing to walk over it, the path is blocked and it has no texture.
The debug log didn't seem to mention anything related, but if you need it (or any other information) please ask and I'll provide it.
Thanks