G string buzz

I have a Luke 111 that has a metallic buzz on mainly the G string.
I’ve had a guitar guy look at it and he says he can’t solve it ?
He suggested swapping out the saddles, but as the guitar is only 2 years old I can’t see that being the issue.
When the trem is pulled back it looks flat and the buzz is more noticeable on when the string is played open.
Any ideas ?