Here is how to get this glitch:

1: Open Minecraft: Java Edition in Snapshot 17w50a.
2: Create a new world with world type set to AMPLIFIED, use the seed 4237599434424850135 and use Creative Mode.
3: Teleport to X: -507 Y: 144 Z: 58
4: You Will see that a tree had spawned on top of a Tree.

Mojang, please fix this.