Terrain paint moved when placing house in a different lot

@AKLSimmer I haven't been able to reproduce this issue in my game.  You mentioned seeing this with lots that you downloaded from the Gallery.  Could you provide an example (the name of the lot plus the creator's ID)?  Or your own build?  Just tag me with @BryonyRae so that I can test further.  Thanks!

I also have had this problem and it's made me cry because I'll spend hours of time and effort to make the terrain paint look nice, only to notice that it's slightly shifted, but here's some things I noticed that might help those who will (hopefully) fix this bug. It happens to me when I either a) place a build from the gallery on a lot that it wasn't built on, b) save my own build to my library and try to place it on a different lot than I originally built it on, or c) rotate a build any degrees (the paint will look nice only on the original angle). Recently I was updating the onsen on Mt. Komorebi, and I wanted to add some terrain paint without the snow getting in my way, but it always snows up there even in build mode, so I saved the build to my library, placed it on a different lot that doesn't have snow on it, painted my terrain, and when I replaced the build, it was backwards. It was only after I rotated it that the terrain paint shifted. I tried going back to temporary lot where I painted the terrain and to other lots of the same and different sizes, but the terrain paint always shifts. I wouldn't mind moving the building and objects to match the new terrain paint location, but because of how slight the shift is (~1/4 tile diagonally), it's impossible to match the building back up. I know this post is old but I really hope my reply gives it some attention!

I have had terrain paint move slightly in every sim game since Sims 2, on literally every lot I have ever placed. In my game, this is nothing new. I have seen it since I started playing Sims 4, just before the Cottage Living expansion. If anything, it is less noticeable in Sims 4 than it was in Sims 2 and Sims 3.

I move lots around all the time, both from my Library and the gallery. Some lots shift more than others, but none of them stay exactly the same. On a few lots it is noticeable enough that I have to do touch up repainting. But some are so slight that I can just leave them as they are.

Lots that have to be reoriented are usually the worst culprits for large shifts. Lots that are a different size than they previously were also tend to shift more. But sometimes it is an elevation change on a particular lot, even if it looks flat, especially if the lot is changed from one world to another where base line elevation differs.

I suspect this is simply a matter of the constraints of the game, and an inconvenience that cannot be avoided, rather than an actual bug. It has been nothing more than that, in my experience, across all the Sims games.