HD Resource Packs still show Phantom Wings incorrectly

Partner Team Reporting: 
Syclone Studios

Verification builds and Platforms:
ver. 1.8.1 build 1483479, ver. 1.9.14.0 RC4 build 1627786

Summary:
HD Resource Packs still display Phantom Wings incorrectly.

Impact:
Causes players to see unintended geometry on Phantoms.

Repro Steps:

     1. Download the "Chroma Hills" or "Pure BDCraft" resource pack from the marketplace.
     2. Create new world with either resource pack enabled.
     3. Spawn in and observe Phantom.

Observed Results:
Grey box is visible underneath Phantom's wings.

Expected Result:
Grey box should be invisible, rendering transparency on the mob.

Regression Build:
-

Notes: