Random light level of 0 in sky

Just created a new world in the latest snapshot and had just begun flying around in creative when I suddenly experienced a lokal area in the middle of the sky with a lightlevel of 0 despite it being in the middle of the day and no blocks are above.
The area extends around 14 blocks in height and affects an area of 4 chunks in an L-shape.

Closing the world and opening it again fixed the problem.

See the attached screenshots for more details

Seed is: -5423339032377826622