The system still seems pretty buggy to me....
I have not experienced any items being released or kicked out of the house, however as Elizabeth points hout it can be difficult to manage the doors and teleporters if you are trying to move them without clearing the plot. I have also noticed that it seems to have a hard time being consistent with its treatment of like items. For instance, I did a customize with 5 fountains of life in my house. All had been turned with the deco tool, were lined up side by side, all with bandages inside... after customize mode, 4 of them returned to their original location, the last one remained a barrel in the moving crate. I also had roughly 11 maniquins on the house (all dressed)... 4 of them disappeared when I entered custom mode, the other 7 were still standing while in custom mode. After committing, the 7 that had remained standing were still in place... the remaining 4 were in the house sign as deeds.