Enderdragon wings render brightness differently (render engine)

The wings of the enderdragon render one wing brighter(fullbright) and the other as if in shadow. (assuming new rendering engine brought this about)

 

+PS if using a texture pack with the 2nd wing layer (Top AND Bottom sides) game will still render both sides, but will appear rather glitchy

 

[attached image is custom texture pack, no other changes, fixed my texture that had both sides of the wing membrane already]