Unwanted War Declaration -Error

[ArthurAVM]

So, I'm playing with Venice and I have great relations with Poland (we have made over 5 Declarations of Friendship, we keep a Friendly relation, we trade a lot, etc). Problem is that when the game reaches turn 266, all of the sudden I declare war at Poland, even though I never wanted to or clicked so in the leader menu.
I've tried saving and loading, revoking protection from city-states but it still happens;
Again, it's not Poland who declares war on me, it's me on them, even though I don't want to.
Has anyone had this bug before? How can you overcome it?
Thanks!

 

[Petek]

Please post a save file from right before the DoW takes place. Thanks!

 

[otaman1]

Did you make a Defensive Pact with some other civ and Poland declares war on them?

 

[ArthurAVM]

So, it seems that Poland had declared war at Greece (I had a Def. Pact with them) but the game hadn't shown that. Anyway I managed to fix it by denouncing Greece before Poland attacked them.
Thanks!