Whether plazma, occuring at extremely high temperatures like on the sun, is a fourth, is debated among some scientists due to the question as to whether it's a gas or not.
From what I just read on the Wiki article, the ambiguity isn't that they don't know if plasma is a gas or not - it's that, at high temperatures and pressures, gases and liquids are indistiguishable.
And of course, when you have only a few atoms - less than several thousand - they exist in absolutely no state at all. This is because the states of matter are not some kind of fundamental organizing principle, but rather ambiguous epiphenomena that emerge from a system containing a sufficient number of atoms.
So, no matter how many "states" there are, the number is functionally meaningless, be it 3 or any other number; and so should certainly not be taken as an instance of some kind of "magic number", as I sense Hovind was trying to do.