Z271 flickering

Hi all,
Having a bit of an issue with my Z271. When I play on games like witcher 3 and PUBG, my screen tends to flicker (like a brightness contrast).
I believe the problem may be to do with the G-sync module as when I disable g-sync the very annoying flickering stops.
I've come across a few people who had similar problems. Has anyone on here had similar experience? I have requested an RMA for direct replacement with the distributor I purchased from, but I'm concerned as to this would solve the problem, i.e is it a consistent problem with this model?

My system specs:
I5 7600
GTX 1070
16GB RAM
650W PSU (EVGA G2)

Many thanks