Giant jungle tree leaves are generated far enough from the tree that upon receiving a block update, they will decay without any logs getting removed. This has been fixed in the Java version by setting the leaf decay distance to 6 instead of 4, but persists in the bedrock version.

To reproduce:

1 start a new world

2 find a giant jungle tree

3 place and remove a block next to the top layer of leaves

4 wait for leaves to decay