When having a mob head in the hotbar / inventory / UI, transparent blocks change texture in the hotbar / inventory / UI.

This also occurs with glass, stained glass / panes, slime blocks, and regular ice.

What I expected to happen was for the leaves to not change texture.

What actually happened was that the leaves changed texture.

Steps To Reproduce:

1. Place down a mob head (any type) in the hotbar (any slot will work).
2. Open up the creative inventory (with leaves).
3. Notice how the leaves change texture.

Note that this only occurs in the creative inventory / hotbar and the survival hotbar. I can't seem to reproduce this in the survival inventory.