I've run into these bugs on more than one occasion and I don't know how to recreate them but they are sometimes connected and sometimes not. I've only experienced this in blitz games.
1: Sometimes a piece is moved but it doesn't take effect and the timer stays ticking on my clock, but I can't move another piece (i have submit moves button turned off.) The result is that you will lose on time because there's nothing you can do.
2: Sometimes pieces will disappear from the board, but they are actually still there (invisible.) After moving a piece it will just vanish. But it's still there for the other player.
3: This one I haven't seen in a while - maybe it was fixed but I'll put it here anyway. The times would change sides if the device was accidentally rotated causing the app to auto orient. Normally my time is displayed on the bottom, my opponents on the top. After rotating the device, my time would be on top (with the opposite color orb) and ticking and I would now have my opponents time.
ie: If I am black and have 3:00 left and my opponent is white and has 2:00 left. Rotating would sometimes give me the 2:00 and my opponent the 3:00 and when it was my turn it would show the white orb at the top of the screen. It's very odd.
I'm on an iPhone 3gs with iOS 5.1
Doesn't work at all! I never could give a cent to a server who broke all my games : "reconnecting... Loading game..." and eat all y time! What a bad site!