Pale Oak Trees sometimes generate without proper support

The dirt support below Pale Oak Trees sometimes doesn't integrate into the terrain properly.
1. On the left of the attached image, the dirt support generated ontop of grass blocks which shouldn't be possible.
2. On the right, it generated half suspened. On the second image below, its only 1/4 supported. (This may even result in the fully floating generation of these trees).

Example Seed: 6002563379176398628
Teleport Command: /tp @s 2747 91 143