Is it normal to have sink water come out of drain connector?

Is it normal to have sink water come out of drain connector?

I’ve had draining issues with dishwashers in the past and now have a new one. The appliance guy said my drain hose was clogged. My question is: Is it normal to have water pouring (when sink is on) out of the drain hose connector (nipple) when it is not connected? One guy said this shouldn’t happen. I’d hate for my new dishwasher to stop draining correctly. Thanks!!