I just created a new survival world (experimental enabled) to test the latest beta. After I survived the first night and the sun rose, I noticed these dark patches under every tree. The light did not update properly.

Steps to Reproduce:

1. Create a new world (seed: -876781979, experimental enabled)
2. Set the time to night
3. Skip the night using a bed
4. Fly around in creative. You will find trees with dark patches eventually.