It is notoriously hard to replicate things in labs, especially with material science.

This was attempt to do it within 2 days of the paper being published.

To add to that, the original researchers apparently had 10% successes rate in their lab, they wanted to perfect it before publishing their paper.

Bad luck was that it leaked, so to make sure somebody else doesn’t get credit for their work they published what they had within hours.

It likely will take months before this will be verified.