I have already reported this; but the video didn't work and a mod kinda shut it down due to the video not working so here is the working video with a description.

I joined my creative world thats in 19w39a, and I looked up and saw certain areas of tree leaves where very buggy with their lighting. This isn't a duplicate post; this is current and is only in this 1.15 snapshot (retraced back to other snapshots and this glitch hasn't happened).

I do ask one thing: Please don't shut this down. Whether its on my end or mojangs, help will very much be appreciated.

~ Guava