I just finished my first Twilight of the Arnor game as the Thalans. So far, the expansion looks great, but I did run into a problem. During the late game, while I was pushing for a diplomatic victory, the Peace Keepers event occurred.

The Peace Keepers, however, didn't do what it said on the tin. Instead of just attacking warships that are outside their own territory, they started attacking warships (regardless of their location), starbases (I lost one influence base and one mining base to them, but they seemed to leave my other starbases alone), some planets, and shipping lanes. They didn't seem interested in constructors or other civilian ships, but they did destroy my (unarmed) flagship.