Stunna just said in chat that the guy abused an exploit and therefore could use an unhashed seed; so he could predict the rolls. Obviously won't be allowed to withdraw.
Why people abuse exploits like this?
He could earn some buck either by telling Stunna about the bug or by moderating his luck, but the way he did he got no winnings
the way he used the exploit was dumb, betting large amounts that can be seen by other people hmmmm... Obvious way to get caught cheating