I had started a new world in the snapshot to test some things. After starting, I set the time to day and turned off the doDaylightCycle gamerule. After leaving the game running for a bit, I come back to my computer and it is completely dark and mobs are spawning. After setting the time back to day, it remains dark.

I have no idea what causes this.

I have attached the affected world, debug logs after using the command, and a screenshot.