Quote Originally Posted by Fisherking View Post
I have had some very weird DoWs but not that one. I once invaded GB which I had been at war with for ever. I landed two groups. The first group was fine but when I tried to land the second I got the DoW pop up. It said Portugal…but it wouldn’t let me land or quit and was caught in some kind of loop so I had to kill the game to get out of it.
That sounds like the port was damaged by Portuguese ships earlier and not "retaken" by the British. Raided ports (via ship) seem to actually change ownership even after the fleet left. In your case the port was probably still registered as Portuguese.

This can lead to stupid DOW's after a faction is destroyed but some port somewhere is still "owned" by that faction. Big bug that one.

It can also cause troubles for the AI if they don't have armies nearby anyway (e.g. on islands). It it not capable of recruiting a militia unit, retake the port and then disband it again as any human player would.