Distorted ground at scenary, after save reload

Issue: The ground being distord where I build multiple scenary after, every reload.
Crash (y/n): n
Platform (Windows/Mac/Linux): Win10 16Go RAM ; Intel Core i7-8700 : Nvidia Geforce GTX 1050 Ti
Version number: Steam version

Description: Hello! I trying to place multiple scenary building near each them to make a big build for a city. I place add-block to joing them, re-up structure and place them at similar altitude.
But after reload the ground is upper or lesser and distord.
That does the same with coastal build when i add block over the water, the ground advanced.

First time a seen it.

Trying to overhaul it:

After reload:

This is all, I hope this will be helpfull for you. Do you need my save game?

I Have another screenshot but there are off topic. Just one similar with it but not exactly, when I place this building (Tavern), it take the highter point to rise the ground.

I wish you a nice day!