Not to nit pick, but that has been my experience in every single Civ game to this point.
The computer will build a city within a golf drive of my capital. I Build a new city on the other side of my empire from them. They phone me up to tell me not to found cities near them. Or: I am moving troops through my own borders, no where near the aggrieved party. They phone me up to ask if this is a hostile action. Later in the game, they then attempt to pull an Operation Barbarossa on me. The diplomacy in the Civ series has always been fucking scuffed and it irritates the shit out of me. Firaxis say they are going to improve it every time, and many of their cheerleaders clap along with them, but it never gets fixed. The problem is, in a game and genre that takes 500 plus turns, and 35-40 hours for a game play through, by the time the multiple reps required to see the issues are done, many people have already moved on.
More pertinent to your point though, yes in Civ 6 they, on the surface, appeared to give even more weight to how leaders 'act".
Gilgamesh's unique agenda is called Ally of Enkidu. He likes civilizations who are willing to form a long term alliance, and dislikes anyone denouncing or attacking his friends or allies.
When in reality, they all seem to have less diverging personalities then they did before. Which is galling, because it was slim pickin's to begin with.
Civ 6 was one of my biggest gaming disappointments, and that is saying a lot as someone on this board (we who have witnessed the MMO gold rush of the 2000s). From its pathetic difficulty unmodded, to its pigeon holing methods of victory, to the overall cartoony look they are increasing leaning into. Like, the whole point of playing the series is to face off against the Mongols in, say industrial or modern, and imagine Genghis Khan as some alternate universe Napolean, or Stalin, or even go the other way and pretend you are some sort of fascist Mayan state, fighting the Battle of Britain vs a defiant Korea. But that is hard to do when all the leaders look like cartoony Facebook game fare.
The random disasters are just stupid, especially in Apocalypse mode. I have sunk hundreds of hours into this game and still am not sure I even really like it. So many bad design decisions.
Here's the weird part: they said they already learned this lesson. There is an interview with a Civ dev, where they talk about a great idea they had for the franchise. Basically, you would build up your civ, then a hardcore random disaster would strike and you would have to spend most of the game rebuilding your smashed dreams. They thought they would beam with pride at how their players showed fortitude in picking themselves up from the ashes. Only problem was. They playtested it and people despised it. They kept trying to reload and avoid the event, and had had little interest in watching everything they had built be wrecked so devs could see how much resolve they had. So, the developers shelved the idea. Sorry, I can't find that interview atm, I will post it if Ido.