The bug

Deepslate appears to use the same color as stone on maps, despite them being colored very differently.

How to reproduce

1. Run the following commands:

   /fill ~1 ~ ~1 ~10 ~ ~10 minecraft:deepslate
   /fill ~-1 ~ ~-1 ~-10 ~ ~-10 minecraft:stone 

1. Obtain an empty map, and fill the map
   There is no difference between the color of stone and deepslate on the map