Swatches revert to default when items are moved in Build mode

could you please provide the following info:

• Are you using any mods/cc in your game and if so, did you test without them ?
• Which platform are you playing on ?
• Is it random which items you have issues with or always the same ones ? Do please list the items you  are having issues with if it's always the same.

Also having this same issue. I’m on PC, only mods are MCCC and UI cheats, but it still happens when mods are disabled. Weirdly for me, it isn’t changing to the default swatch, it’s changing to the swatch it was when I first place it (so if the default swatch is brown, but I click the white swatch and then place it, it will be white. But then if I change the swatch to let’s say black, it’ll change to black, but if I then move that item, it’ll change to white). 

Try the following

- Close the game
- Rename Documents\Electronic Arts\The Sims 4 to Documents\Electronic Arts\The Sims 4_Old
- Repair the game
- Start the game. All your content will be gone now as the game created a new folder. All your saves/.. is still in the old folder so not to worry. 
- Start a new save game
- Check if you still have the error
- Report back with your results for further steps on how to get your stuff back.