Crimson trees can sometimes generate in the nether terrain. This also probably occurs with warped trees, but i didnt found any warped tree that generated like this.
Seed: -100817776063774199
coords: /execute in minecraft:the_nether run tp @s -98.72 102.87 237.87 -417.59 -18.00
This does happen with warped huge fungi as well, but as per MC-171856 this is working as intended.