I logged in and signed up for league play. I cued and entered one game (and won). League standings had me as one win, one game played. Then because I had to step away for a while I minimized my browser and put my computer to sleep. (I did not even attempt to cue a second game.) When I came back to my computer I got the "you've been disconnected notification" as expected whenever I put my computer to sleep with CH open. However upon logging back in my league standings said 1 win, 2 games played. Somehow I got marked for a loss. It ended up being the difference between 2nd and 4th place (my actual 4th game that according to the league only counted for tiebreak was in fact a win). This was for the Artifact Anarchy league that started at 1pm UTC Sunday April 27th. I'm running Firefox 28.0 and Flash 13.0.0 on Windows 8.1.
Oh if it's helpful, here's a screenshot of the league standings: I only actually played 5 games (for 26 points) but as you can see it says I played 6.