Issues with artificially spawned shulkers

I was experimenting with constructing a small platform out of shulkers under bedrock in the overworld in a flat creative world. I used the command "/summon minecraft:shulker ", and even though the world was on peaceful difficulty, the shulkers still spawned, and instead of being purple, the "Shells" of the shulkers were white. the same occurred when I tried the command on the surface, but the shulkers were normally colored when I used spawn eggs.