Yes, the slot itself becomes frozen not just the weapon. Therefore any weapon that comes into play on your side will become frozen in that slot until the Freeze expires.
If the slot is being frozen, then it should not require a weapon in that slot for it to freeze. Yet voodoo doll + freeze does nothing if your opponent does not have a weapon. So, your explanation does not really make sense.
That being said, this is a known interaction, already reported
here. In the future, please note that you need to search all three bug boards (reporting, archive, and confirmed) or the entire forum to see if your bug has already been reported.