Blocks with flat textures held by player in third person view, villager / iron golem or enderman have z-fighting

The bug

Blocks with flat textures like flowers, mushrooms or rails have z-fighting when rendered in the hand of a player in third person view, villager / iron golem or enderman.

This is not the case for the mushrooms rendered on top of mooshroom cow or for falling block entities.

How to reproduce

Summon an enderman holding a poppy

/summon enderman ~ ~ ~ {NoAI:1b,carriedBlockState:{Name:"minecraft:poppy"}}

How to reproduce (player in third person view)

1. Download the attached resource pack MC-114576.zip and load it
2. Put a poppy in your selected slot or your offhand
3. Switch to third person view (F5)

Code analysis

Based on 1.11.2 decompiled using MCP 9.35 rc1

It looks like culling is not enabled before the block is rendered.