Yes, that's annoying and quite common on many flash casinos - it appears any new window you open when closing the game, or the background window with your account login box and balance don't realize you're still logged in after a certain period of inactivity (while you're playing a game) and then make you login again whereby they update.
Inetbet flash does this, as did Wintingo as I remember.
NordicBet and Betsson don't.
Not as annoying as putting in loads of man hours to have that very thing fixed, having it completely tested it and now all of a sudden it happens again and I can't replicate it. It is kind of like hearing that rattle coming from your car engine, taking it to the mechanic and then it is not there.
I am thinking that it could be something to do with the separate page for the game area as when you play at NordicBet you stay on the same URL.
Thanks Dunover, I think your last comment might have solved it!!
Cheers,
Ben