What's up with grunts' eyes in Halo 5?

In all the Halo film, games, and cutscenes I’ve seen before Halo 5, the grunts had eyelids and relatively humanlike facial expressions. In Halo 5, during the non-combat segments, I looked at the grunts standing around, and they all had crazy bug-eyes that made them all look like psychopaths.
Call me nit-picky, but I wouldn’t mean seeing the grunts faces improved upon in an update.