No fungus (crimson/warped trees, crimson/warped mushrooms) in the Nether

There doesn't appear to be any crimson/warped fungi in the Nether, I can confirm that this is a bug because I tested it in 2 different launchers (MultiMC and Official Minecraft Launcher) and in 3 different worlds, a single-biome world (creative, no seed) and 2 normal worlds (creative, no seed).