In snapshot 16w39b, mobs which now display the Elytra (Skeletons, Zombies, Armor Stands) cause rendering issues when an Elytra is equipped.

The ghostly transparency glitching seems to occur randomly depending on the number and proximity of entities with elytra equipped.

To reproduce:
summon in a bunch of Armor Stands (or skeletons, or zombies) equipped with the elytra:

/summon armor_stand ~ ~ ~ {ArmorItems:[{},{},

,{}],FallFlying:1b}

When they land, transparency issues should appear on either the Elytra itself or the entire entity. Sometimes even non-associated entities that just happen to be nearby.

See screenshots for examples.