@Recursive AI seems to have their ship promotion logic backwards. Brazil tried a surprise attack on one of my cities using Targeting ships, and when those were rebuffed by my own ships he cycled them out and started attacking my ships with a ton of Bombardment frigates.
Also some of their diplomacy choices are... strange. Hiawatha has shown friendly the whole game, then abruptly went hostile and started building up near one of our borders, then asked for a DoF (that I accepted knowing full well he was was lying through his teeth), asked for a joint war declaration on America that I refused because I'm not quite that stupid, then a few turns later went full backstab with a denunciation.
Bug reports go on Github, please.
Hiawatha's behavior could be due to a number of reasons, I'm not sure whether I'd call that a bug - unless you're seeing this consistently.