I have several other saves to show the progression across two different games.  Both were on the same map.  In both cases, it was the city located in the same spot.  The city owner in both cases rose to an insane score early in the game due to a city level that had skyrocketed inappropriately.  Once I conquered the city, I gained the same score.  It really messes with the game dynamics.

https://www.dropbox.com/sh/rm6dkpcr0yftzba/AACHDC4amML8FIMCJmk2vmQ9a?dl=0

Screenshot is there to show the city level is 258 and my faction power is 67026.  Earlier in the same game, while most other players were around 40, the player with this city had a faction power of 600 or something.