marker Armorstands appear black in blocks

I created an ArmorStand (placed it down) and
execute 2 commands:

tp @e[type=ArmorStand,r=5,c=1] ~ ~-0.5 ~
entitydata @e[type=ArmorStand,r=5,c=1] {Marker:1b}

now there is a marker Armorstand in the ground
and it's black, but if I remove the marker tag with

entitydata @e[type=ArmorStand,r=5,c=1] {Marker:0b}

it's looks normal

therefore the block on the head is also black.