Any block with an data value that has no texture shows the missing texture texture. I'm not sure if this is a bug or not, but figured it couldn't hurt to post it. For example, block "grass" with a data value of 6 will show the missing texture texture. Using this command, you can see this:
/setblock ~ ~3 ~ grass 6
This does not occur in previous versions; in previous versions, the block would just display as the block without the data value, so grass:6 would just appear as grass.
The picture attached is of grass with a data value of 6. This also occurs with any other block without a textured data value. For example, wool with a data value of 15 will have a texture, but glass with a data value of 15 will not, because wool:15 is black wool; there is a texture for it.