I just got my Pixel 2 XL delivered to me yesterday. Set it all up, didn't get the flashing screen issue at first but now it's doing it. Tried to chat with Pixel support from my phone, they don't have a resolution for it yet.... Hopefully it's a software issue?
It seems really random. I had it flashing when I rebooted. Also did it when I was in safe mode.
Since my phone is only a day old, I'll hold onto it, keep observing and see if there's a fix soon.
I just received my Pixel 2 XL and having the same screen flickering problem too. I tried a factory reset but it is still there. Really hope there is a fix soon. In the mean time, back to my reliable Huawei P9