Ideas
I have a sim. Every time I try to move her from one lot to another (Using the phone > Move Household) I select "Keep Furniture" on the move. Sim has plenty of money left over. I move, open the lot and all of her possessions that were not already in the inventory are gone.
The items in the household inventory are still there.
I did not have mods on when it happened (I haven't turned them on since 12/2 update), but there were mods in the save. I did have several storage items, like the sticker box and a household keepsake box.
LadyAlpha001 When you move a sim and keep the furniture, the only thing that ends up in a sim's personal inventory is whatever was in it before you moved. When you keep the furniture, everything goes into the household inventory. Nothing goes into the sim's personal inventory. From what you described, it sounds like everything is working as designed. Now, obviously you've lost some things in the move, so something happened you weren't expecting. I suspect that the things you lost were in a container of some sort (storage chest, fridge, DU student chest, cardboard sticker box, keepsake box, etc.). Is that what happened or was it something else?
When you move, it is always best to empty the containers and either place the contents in a sims or household inventory before you move. Don't rely on the containers keeping their contents when they go into the household inventory when you move. And if you save a copy of the sim or lot to your Library and reinstall them, everything in both inventories is gone as well as everything that was in any container on the lot.
Hope this helps.