I have created a new world, with city settings on ... they loaded the way I wanted them to.

I did not quit the game, I just logged out of the world to the main menu.

I deleted that world, and created a new world, but this time, I set LC to disabled, but, magically, they still generated. Whether or not this is due to the world having the same name "new world" for each new world I generated after deleting the old "new world," or it is session based, I do not know. But, what I do know that the LC data is not stored in a manner that gets deleted when the world is deleted, which is problematic.

Playing 1.16.5.36.0.43 Forge, ATM6-1.5.3b, lostcities-1.16-4.0.7-beta.

After testing some more, I created another new world, this time, with a different name, and the lost cities still generated, even though the settings are clearly set to disabled.

So, I decided to close Minecraft completely, and load it up again. Again, I created a world called by default "new world," and ... no cities, finally.

So, it is confirmed, LC does not remove it settings from memory between each load and upload of new or existing worlds.

Just wanted to second this post. Was doing some testing of my own this morning and I found that whatever settings you had set when you generate your first map (after starting the game fresh) LC seems to lock into and wont change until you have closed and restarted the game all together. For example if I generate a vanilla map with LC disabled and then go back to the menu and try to make a new game with LC enabled, even tho it appears enabled in the UI the world will not have any cities in it. Same goes for starting with an LC enabled world. Can only restart the game to change this.

Forge Version 36.1.0
Mod Version: lostcities-1.16-4.0.7-beta.jar

Thanks for reporting. I'll check this out (soon)