I attacked a castle type with a stack. The castle defending army only has a general unit. There is a stack of enemy stack nearby as reinforcement.

The castle has 2 gateways. Call them A and B
So i attacked with rams at gateway A. Quickly bashed down gateway A and send my horses to capture gateway B, a note saying I have captured the gateway.
Then i settle my forces at gateway A to wait for the reinforcements while i finish the lone general at the townsquare.
The reinforcements didnt make way to gateway A but gateway B instead. They walked to gateway B and it opened and a note say that i have lost the gateway !
What happens next is not important.

I remembered that this will not happen in the previous versions. Is this supposed to happen ? Do u ppl experience this too ?