Which map are you playing on that has so many settle-able spots?

Dustbowl is also a great map, settle-able spots are not too common, and the high seas hold secrets.

There is some strange stuff going on with ZoC, and Bloom of Twilight not working properly. Essentially with big ZoC you are guaranteed settling spots after a while next to your original city, while BoT that should do it at a cost, does not work. I think it has been like this since 1.2, but not sure.

(Just for reference, My Huge custom map, by then end I had 60 cities.. on Desert tileset, something is very wrong with that)

I would argue that it's not the "Maps" add-on that is causing this.  There are too many "settle-able" spots and new cities are allowed to be too close together in the regular game.  They should really tune this back one notch (or one tile as the case may be).