You’d have one postdoc do the pipetting and the experiment worked. Another person tried, following the same procedures with the same equipment in the same room at the same time of day in the same environment … experiment failed.
My takeaway was that a lot of this bio stuff is inherently flakey and/or poorly understood. We kinda mostly know what’s going but it’s really lots of trial and error and chasing statistical variations/effects. Best you can do is “it works N% of the time”
You can have a system where 100% of researchers have failed to replicate another experimental result while 99.999% of results are replicable.
That's not to suggest that's what's actually happening here, because the replication crisis is well discussed, but it's not a good statistic to measure things with.
Unfortunately published data so far is highly questionable. I can totally confirm this quote from wikipedia:
"A 2016 survey by Nature on 1,576 researchers [..] on reproducibility found that more than 70% of researchers have tried and failed to reproduce another scientist's experiment results (including 87% of chemists, 77% of biologists, 69% of physicists and engineers [...]" https://en.wikipedia.org/wiki/Replication_crisis