Azalea/flowering azalea don't create hanging roots under rooted dirt when it create azalea tree

When you create azalea tree using azalea/flowering azalea, it will create rooted dirt under it, but it will not create hanging roots under it when there is some space under the rooted dirt. This can be WAI but i thing that it would make sense if it would create hanging roots under it.

How to reproduce

1. Place azalea/flowering azalea

2. Remove the block under the block under the azalea

3. Bone meal the azalea until it will create azalea tree