When Envy skull is actived on first person mode playing as John aka the masterchief, however he didn’t fully invisible you still can visible his legs and also you can see weapon’s ammo on INSIDE shotgun or brute shot while being invisible mode.
Just letting you 343i know about this bugs/glicthes. Thanks for reading 
and keep up the great work on halo 5 guardian can’t wait to own it, but i would like to see halomcc working also