Currently when you buy furniture rare/supreme from another player and it's to heavy the only way to move it or transfer permissions is by loading. Normally when you load/unload it you are now the owner. Not with benches, and there might be other items that are like this. I recently bought a wooden bench (supreme) from another player and I was confused why I couldn't rename it or secure it as a mayor of my deed.
[13:17:26] You do not have permission to secure that. (Supreme wooden bench I bought)
I created one for testing purposes. As you noticed I can't rename it.
Now I'm sure this is not the only item like this, here is a suggestion, if you load/unload something you should be the new owner. Currently there is no way to transfer permissions. Thanks for your time.
It might be possible for theft even, check that!