First of all, sorry for making a separate discussion here, I can't find the way to comment on the mod, so I had to make it this way.
The problem I'm having is, around 1550s, the game freezes, then crashes unexpectedly, without any war starting or anything, it just happens after a few days. I looked up in error.log, last entry is
So i commented in LCLC_largest_city_scripted_effects.txt every function in the code, and it seems to work afterwards. Again, I'm not that skilled with modding, and this might be accident, but it worked for me so far, but still I want to write it here in case it's actually a bug from the mod itself.
Sorry again for writing here, hopefully it will be useful to both author and the others

Thanks for detailed report!

I didn't take into account ongoing save when adding feature on last update (1.0.5). I'll post a fix later.

Before the update, you can open the Large and Largest: Mod Options in decision then set the Number of Large City in the Region (default is 10). I think it should be empty now in your save. On fresh save, the variable is set on initial event. On ongoing save it is not set, leading to a ctd because the game divide by zero.

I'll look into it, thanks for answering. If anything similar happens again I'll try to report again

Just updated the mod. Do share if you encountered any issue with it.