The bug

Trees/Leaves too bright under big platform

To reproduce

• Spawn a big stone platform (~50x50 to clearly see it)
• Reload world to fix client syncing issues
• Notice that the leaves (or any other semi-transparent block) seem to emit light

The reason for this (and the solution) can be found here: https://github.com/MinecraftForge/MinecraftForge/pull/3871

Note: This is unrelated to MC-55730