Toggling “HD” mode will override custom terrain textures in custom-made maps.
Example: Map overrides the entire Cityscape Tileset with modern roads & pavement (using “import file” in World Editor to use exact texture paths as Cityscape tiles). Playing such map in reforged mode will use the default Cityscape tiles instead of the custom modern ones, thus breaking the map theme.
New reforged graphics override these since I think there is a conflict/priority there for the HD textures to override whatever’s in the map. This is an issue with old maps with authors that are no longer around to update them (i.e. re-save map to comply with new texture definitions).
This generally creates an annoying problem: Constantly annoy people to turn off their HD mode when playing the map, an untenable solution (+ you can’t turn off HD mode while already playing map).
Solution: Give map-specific files priority over any default graphics (right now HD > MapDefined > SD, make -> MapDefined > HD > SD).