Interesting. Some people are getting strong diamagnetism at RTP, and now someone is actually seeing zero resistance at a low temperature. I'd take this as mildly positive news. It would be a surprising material if it were a high Tc (only in the LN2 sense) superconductor that is also strongly diamagnetic at room temperature (though I'm not sure if that's more surprising than a RTP superconductor).
It's confusing. You'd expect both to be present or none, it is strange to have a material that is conducting and diamagnetic at room temperature and that shows super conductivity at much lower temperature. You'd expect the diamagnetism to disappear with the superconductivity.
Observed effects which have been given a name != a single universal truth. Just because we have experimental evidence of effects and theoretical explanations for their occurrence prove we actually have defined the underlying phenomenon's which produce the observed effect accurately. The reason we experiment isn't to prove our theories are correct so much as it is to probe where they break down so we can further refine our understanding of the universe. What we are likely seeing here is the result of an organized pattern of atomic nucleii forming a lattice which creates the conditions for the movement of electrons to be easier (or harder) than expected at certain temperatures (with temperature being the property which induces strain on the lattice). This is very crude, but begins to explain the multitude of factors at play here.