That's exactly what I thought at first. And then I realised that the 'ferromagnetism+diamagnetism' article does not actually provide a mundane explanation of th

That's exactly what I thought at first. And then I realised that the 'ferromagnetism+diamagnetism' article does not actually provide a mundane explanation of the "half levitation": They estimated that their sample had very strong diamagnetism -- at least the 2nd strongest of any known (non-SC) substance, assuming their sample was pure (but we can assumeit isn't, considering that they just had one tiny flake levitate), so quite possibly the strongest. And superconductivity is a possible cause of diamagnetism. It still hugely weakens the levitation effect as evidence for SC, but "conclusively show that it is not superconductivity" is not quite true.