Yea, I have the exact same issue. My case may be a little more specialized, though: I had just run into the 'clicking play does nothing' bug, and did the hotfix prescribed here: http://na.leagueoflegends.com/board/....php?t=2423574
and after doing that the game seemed to run fine, even getting me through champion select, but just as shown above I ran into the error of 'Game is still in progress' without ever loading up either the League of Legends splash logo or the 10 champions.
I can also confirm that you run into the so-called 'reconnect' button loop, where you press the button, the screen you clicked it on is minimized and removed, yet another one takes its place (minimized) nearly instantaneously.