The city often gets cut off from the new terrain generation in 1.18/1.19, this is often seen in village generation nearby or the city trying to generate within the village.
As for the generation itself, can be easily tested with Amplified world type.

Version: lostcities-1.18-5.3.13.jar
Forge: 1.18.2 - 40.2.0

Reproduce Steps:

1. Install the lostcities mod.
2. Select the standard profile and generate a city.
3. Look for extreme heights biomes, for an example stony peaks, jungle, mountains etc, or just a village.
4. Notice that the terrain and smoothen sometimes get cut off from the city, or from the terrain itself.