If it was a mixing texture the it would look totally different. And not as abrupt, I mean the tile is destroyed, so not a missing texture.
Here are some examples of missing textures that have happened to me.
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Even though that was from Skyrim it still follows the same concepts etc.
Another giveaway that a texture is missing is when you can see through an object. For example when you glitch into spots and you can see through walls it's because the texture is missing. Plus if it was actually missing IW would have addressed it because this has been brought up by people on xbox who got the maps way before Elite PS3 members.