Tuff Slabs do not appear on maps

Confirmed, The maps seems causing a dirt map displayed and filled Tuff slab's map are slower generate the minimap, Also affects with Android.

Steps to reproduce

1. Create a fill commands using or Place around the line of tuff related slabs

   /Fill ~ ~ ~ ~20 ~ ~20 tuff_slab
   /Fill ~ ~ ~ ~20 ~ ~20 tuff_brick_slab
   /Fill ~ ~ ~ ~20 ~ ~20 bamboo_slab

1. Take empty maps and then create a map for target

Observed Result: The tuff slabs map causes a slow generating speed and same color as dirt after created the map, The placed tuff slabs does not generate the maps display

Expected Behavior: When the filled tuff slabs and created map can should be match the color the tuff slab's colors and the generation would be same speed, When placed tuff slabs would generate correctly the maps display