I have found vrr flicker in Windows. It was caused by a couple of apps I had installed. Razer synapse when open causing vrr flicker in windows + I had a program called fancontrol which also triggered it. But again, it is setup reliant, as when I changed motherboard the fancontrol stopped flicker, but synapse still did. Could be that Darren1967 has an app installed that is triggering it.It's not that didn't notice it I was purposely looking for it because that was the reason I disabled vvr to see if it was needed when you've got 360hz refresh. My conclusion was not really but seen as flicker isn't an issue either I renabled it.
Maybe you have a faulty screen . You did mention you had flicker in Windows didn't you? That shouldn't be happening