Debug chunk borders visual glitch

Backstory:
I decided to try the new 19w44a snapshot today, and tried to use the new honey blocks and slime blocks in a flying machine.
As I was riding it, I turned on chunk borders and flew up. The outline between the bottom of the world's blocks at y=1 and the chunk borders at the bottom made it possible to see throught the bottom of there world slightly, as seen in the picture.