Blocks (more noticeable on custom block models) cast shadows onto themselves, or they just have dark spots on them, noticeably near the bottom of them. In this example, I used a Pig model and a custom plant-like model (with an edited gunpowder texture on it). The Pig's back legs' fronts are dark, and the whole gunpowder plant-looking thing is dark (I'm holding the item as a comparison). The other example includes a chicken model (with dark feet).

Steps to Reproduce:

Make a custom block model and put it onto a custom block.

What I expected to happen was...:

The model should be nice and bright.

What actually happened was...:

The model has a dark point(s) on some portions of it.