Hey, So I found this bug! when you have an elytra on a armor stand it becomes transparent which is cool. But when you press F3 then you can see it which looks like a bug! I also really liked the transparent elytra you should add a enchantment to make it transparent! its better when you dont want to have huge elytras on so they can see your nice skin!
Did you mean to say F5, instead of F3? Also, I believe this is a duplicate of MC-109587.