Large Area of No Light in Overworld in Broad Day light

Created a brand new world in survival mode and started exploring.  Ran into what appears to be a series of chunks in a line that had no light.  

All the usual mobs that spawn at night were present inside that strip of darkness.  I was able to walk through it and everything seemed normal other than the lack of light.

Exited to main menu and back in and the lighting was restored to normal.