those 4 clips arent pushed all the way in. got to get your hand in behind the grill by taking out the pin/clips things on top and push that #### in while supporting from behind.
what causes it, is holden techs rushing when refitting the front bar. Only happens to mine EVERY time it goes in under warranty. As above, just needs to be clipped in properly.
I read on another forum that a guy filled that space in with those Audi-esque LED strips. He's gonna be awful pissed when he finds out his grille wasn't clipped back in properly.