The bug

When a sapling is grown into a tree, existing leaf blocks adjacent to the newly grown tree trunk will have their distance attribute altered due the newly generated log.

There is an inconsistency in observers being able to detect this, sometimes observers will not detect the leaf block distance changing despite the attribute indeed changing.

Leaf blocks closest to the sapling will almost always update the observers, however it becomes inconsistent the further the leaf block is (up to the limit of 7).

Expected behavior

Observers should always consistently detect leaf block distance attribute updating when a log is generated from saplings that are grown next to them.

Steps to reproduce

1. Set up an observer to detect leaf blocks next to a sapling
2. Bonemeal the sapling
3. See that the observers are not consistently activated, especially those watching leaves further away from the generated log.

I have provided a world with a testing setup to reproduce this.