AI Memory bug?

In a recent game as the Julii, Britannia declared war on me and attacked some of my cities, so I went and killed their armies and king and then took their city on the mainland.

I put a diplomat there and asked for ceasefire with a large-ish money bribe, because I was busy fighting the Gauls and didnt feel like messing with Britannia. The Britons said Alright, ceasefire and left me alone.

Next turn - Britannia declares war and attacks the city I took for them. Ceasefire with another bribe, they accept.

Next turn - Britannia declares war and attacks the same city with the same troops, I dont feel like giving them more money, so I just ask for a plain Ceasefire, they accept.

Next turn - Britannia declares war and attacks AGAIN and I do a plain Ceasefire again and they accept again. Next turn they do the same thing and I do the same thing and they accept.

So basically, for the rest of the game, Britannia would declare war and then accept peace every turn..

Your patience is commendable however I advise to sod the Gauls. Go attack the Brits. Their just taking the piss.