Rendering issue with flat entities

I'm having rendering issues with the current snapshot.

This is being issued as one bug because I believe it comes from the same place (because of the new rendering tests.

Outlines on "flat" items and entities outside of the player's body are having a problem with what I think is their transparency.

Both attached images present problems with the squared outlines of these entities. on block-like entities the issue is mostly present in item frames.