I also have this problem. If I save again and reload, ANOTHER carriage appears clipped into the one that is already clipped into the shop. This is gamebreaking and it seems a decent amount of folks have this error.
Win7 64bit, 16gb RAM, Intel i5-7600k @ 3.8GHz, GTX 1050 Ti 4gb.
All of my drivers are updated.
Eidt: Was originally playing the 32bit version of the game because people said it was more stable. I DL the 64bit version and the cart in room bug was gone. now, I get the bug where the items in the bedroom multiply upon saving and loading a game. It is playable at least.