Different slot games may use different default bet amounts when first opened. In many cases, the default bet is based partly on your current coin balance, which means players with larger balances may see higher starting bets on some games. Your available maximum bet may also increase as your player level increases.
Because of this, your default bet amount may be different from what you were previously wagering when you change machines or launch a new game. Always review your selected bet amount before you start spinning, especially when switching to a new game.