To replicate the issue open up a custom game - change some of the settings in this area such as the Real Estate and Commercial Capacity or the city cash level:
![Image](https://i.ibb.co/njXhkX4/CES-Settings.png)
After that open up any of the official CES DLC Scenarios and check the settings.
![Image](https://i.ibb.co/Fm6tB6j/DLC-Scenarios.png)
You will notice that they are the same as what you set in the custom game.
![Image](https://i.ibb.co/njXhkX4/CES-Settings.png)
This is an important oversight as you can end up setting the scenarios to be too easy or too hard then intended and the difficulty level setting at the bottom of the scenario selection window (the part where it says Difficulty Level: Original Difficulty) does not have any effect on it either.