I too lose my saves on a frequent basis. I return to main menu before I leave the page.
I've disabled pepperflash so that can't be it.
It's sad because I bought the premium content. If I buy premium content, why can't I get cloud saves?
The UI design is too busy. The tutorial is too obtrusive. The Engrish is pretty bad. There are too many steps to play the game, steps that break some fundamental design rules.
If the game were play tested, it might be a little more fun.