I also have the screen flicker issue and it goes away by switching to some other app and then back to PG2 (by alt+tab)

Thanks Harb...this works

Unfortunately the match does not end when you capture all the cities so my opponent will not show up for the remaining turns.

I have been getting flicker as well, it started in March having been fine for over 400 hours. I reduced the refresh rate and unchecked the steam overlay but its still occurring after about an hours play. I even tried offline mode but its not improved.

Any further ideas?

This problem has just started, scenario begins fine, then after about an hour starts to rapidly flicker.
It only happens in game.
Any ideas?