Nether fossils still very rarely can generate in mid-air, don't really know if it may be caused by some kind of generation-fail or cave generater, but it sure is related to fossils

seed: -2307589128541860495

coords: /execute in minecraft:the_nether run tp @s -55.16 41.74 -46.42 -573.00 52.20

world: superflat void