Product: The Sims 4
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What is your current game version number? 22.214.171.1240
What expansions, game packs, and stuff packs do you have installed? Holiday Celebration, Grim's Goulish Guitar.
Steps: How can we find the bug ourselves? By building a basement that falls inline with the first story walls.
What happens when the bug occurs? The terrian outside the building rises. It breaks padios thing in the Sandtrap Flat in Oasis Springs. As you can see from the includes image, on the left side of the house the basement's exterior wall doesnt fall on the same place as the ground level's extiror wall; while both extiror walls for the basement and ground floor do line up on the right side of the house.
What do you expect to see? The terrian to stay the same height.
Have you installed any customization with the game, e.g. Custom Content or Mods? Never used.
Did this issue appear after a specific patch or change you made to your system? Neutral/Not Sure
so when you build a basement in the Sandtrap Flat on Oasis springs, and you make the basement's exteiror wall line up with the exterior wall of the ground floor, you get a mound of dirt all around the walls where the basement and ground floor's exterior walls line up, and theirs no way to fix it in game, other than deleting the basement.
This is basically "as intended", I use it for landscaping for example.
If you do not want this happening, move your basement down with the vertical up and down errors in the center of the basement.