Ui flickers with some g-sync - mainloop fps combinations

hi all,

Using 2022.5.0 preview 0676, my ui flickers slightly when the vvvv window is active.
I can reproduce it with a fresh patch, and a single stride render window. I could not capture it on the machine itself, maybe because the max fps recording is 60fps and my monitor is 120fps.did my best with the smartphone

monitor 120fps, patch 60fps no g-sync no flicker
monitor 120fps, patch 120fps, with g-sync no flicker
does not occur with stable 2021.4.12