One lab is definitely not adequate.

Replication attempts don't give you an unambiguous signal, many things can go wrong.

If one lab hasn't succeeded in replicating the paper, does that mean the paper is wrong, or just that a necessary step wasn't documented clearly or followed correctly?

More labs trying to replicate give you more independent signals.

Depends on the finding.

Getting a false negative from a lab is plausible.

Getting a false positive seems very unlikely.

Cold fusion got several false positives very quickly.

And if this is a diamagnetic that seems to do some of the right behavior, a false positive is quite possible here as well.

Hopefully all corrected in time.

Although the experimental protocol had not been published, physicists in several countries attempted, and failed, to replicate the excess heat phenomenon. The first paper submitted to Nature reproducing excess heat, although it passed peer review, was rejected because most similar experiments were negative and there were no theories that could explain a positive result;[notes 2][42] this paper was later accepted for publication by the journal Fusion Technology. Nathan Lewis, professor of chemistry at the California Institute of Technology, led one of the most ambitious validation efforts, trying many variations on the experiment without success,[43] while CERN physicist Douglas R. O. Morrison said that "essentially all" attempts in Western Europe had failed.

https://en.m.wikipedia.org/wiki/Cold_fusion

But if one lab *does* succeed, it means there probably is something of substance.

Cold fusion also replicated across multiple labs, before they all retracted shortly after.

My memory is fuzzy, but my recollection is that Pons & Fleischmann's non-discovery involved unclear "waste heat" measurements, and a setup that wasn't well described, making it difficult for other researchers to duplicate. That would seem to contrast with Sukbae Lee, Ji-Hoon Kim, and Young-Wan Kwon's work, where everything suggests they've provided a readily replicable description of the material and process, and the evidence (magnetic levitation) is going to be pretty obvious.

If one lab fails they may have fucked up. If one lab succeeds then it’s very noteworthy.

This is a fairly straight forward claim. It’s not like “most science” with dubiously small effect sizes that may not replicate.

when an "adversarial" lab (as in, competing with the original lab) tries to replicate and succeeds, you can be pretty damn sure it's legit.