Leaves Placed in Creative Decaying

I was making a paintball arena to show off for some friends on a server I like to play on in the PC version, and hoping to recreate it on the server. It was a Skyblock 5 times the normal size but when I began on the tree, I was making an outline when I noticed that the leaves to the giant tree was missing.

What I expected to happen was...:
The leaves that I placed in Creative would stay and not decay

What actually happened was...:
They decayed anyways.

Steps to Reproduce:
1. Load a world in creative mode.
2. Place leaves far away from trees, so they don't get stopped from decaying.
3. Wait and watch them decay