Yes, there are occasions when there is Slippage. If the price trades through the specified Stop-Loss level, an order is activated to close the position at the prevailing market price at that time. Should the market be trading at a different level from the stop-loss level at that precise moment of execution, then the stop may be filled at a better or worse price. Slippage should be a consideration when placing stop-loss orders, as Crypto currencies can be at times extremely illiquid and volatile. There could also be a slippage event when executing market orders, in case of a price movement.