I noticed this too, but only with the brooms. In my case, sometimes I would be flying somewhere, change my mind, and give my sim a different destination, whereupon he would dismount, and instead of remounting his broom, would take a cab. The broom would be gone from previous visited locations, but the racjk at home, while empty, would not accept a new broom until I deleted it and bought a new one. I developed a workaround that seems to work for me. When I buy a broom for my sim, I put it into his inventory before he even leaves the house. Then I delete the Broomstick stand. I haven't have a sim lose a broom yet, using this system. YMMV*
* I suspect I may have attempted several "fixes" while I was still troubleshooting and that might not be what fixed it. I may be overlooking something else but I'll try using the stands again (now that my sim can afford to use broomsticks as a more-or-less disposable item) to see if the problem still exists. You're welcome to give it a shot and see if it helps.
