Same issue! So, everything was fine for me (in Vienna) and my friend (in Frankfurt) until few weeks back. What basically happens is, some games instantly start with loss/choke indication and the game is simply not playable, beacuse the screen just jumps around (for both of us). It ALWAYS happens to both of us simultaneously (100%). We then try to leave the game or die instantly, however the game wont connect to lobby so we need to ALT+F4. After that, we chage the server and everything is fine again for a few games, then rinse-repeat. We found that the Belgian Servers are more stable (it happened there only twice), whereas the Frankfurt servers are trash. I am saying it is the servers, because if it were the connections (both +175MB connceitons with low latency) there would be no chance that both of us face the same issue 100% simultaneoulsy. Is there a known issue/fix? Maybe we need to change some connectivity settings? Can it be due to Windows?
