I've done a lot of testing to find out the rules of bugs: when I start or restart the game, the lostcities-server.toml in the first world I enter or generate will take effect. But when I quit to title and enter or generate another world, the lostcities-server.toml in effect is still the first world's.

If the lostcities-server.toml of the first world you enter has cities, even if the lostcities-server.toml of the second world doesn't have cities, it will generate cities in new chunks.

If the lostcities-server.toml of the first world you enter doesn't have cities, even if the lostcities-server.toml of the second world has cities, it will not generate cities in new chunks.
It seems that the lostcities-server.toml isn't refreshed when entering the second world

version lostcities-1.15-3.0.1-alpha

In addition, when will the next alpha version be released?

I will check this out soon. Sorry have been a bit busy with my other mods

I can confirm that this issue still exists with version 3.0.2-alpha. The first time a world is created the generation settings will be respected, but creating any additional worlds will use the same settings as the first world, even if different settings were chosen. The only way to fix this is to relaunch the game. Based on this message from the log that appears every time the game is opened:
[modloading-worker-5/INFO] [lostcities/]: Creating standard profiles into 'config/lostcity_profiles'
I am guessing that restoring the default profiles might have something to do with fixing it. Take that with a grain of salt though. I am also seeing the "configuration file is not correct" errors mentioned in #276.