> The result of the combination of the above two is that the iron impurity is attracted to magnets, but the rest of the LK99 material is repelled. This makes samples "stand up", but not hover like a true superconductor would. All of the third-party reproductions showed this effect, none showed samples truly floating.

Thanks for the explanation.

But wow, I'm kind of amazed at the simplicity of the error - iron impurities when you are testing for magnetism! I mean, who would have thought this could be a problem, before announcing this to the world?!