Lighting bug with maps in item frames

Maps, placed in item Frames doesn't Change the light Level (full bright at every time)
STEPS TO REPRODUCE:
1. Generate a new World in Creative mode
2. Take an empty map from Inventory
3. Activate it
4. Fly around until the map has enough shown area (unaffected, how big it is)
5. Place it into an item Frame
6. Set the time to night

WHAT I EXPECTED TO HAPPEN WAS:
The Map become dark when Setting night

WHAT ACTUALLY HAPPENED WAS:
The map Holding light on maximal luminance