I'm surprised they only found one gap. I would have expected multiple (fixable) gaps would have been uncovered, especially since the result was spread over many papers by many different people.

In [1] they claim:

>However, there were 34 noteworthy deviations from the published record that needed to be resolved, the most substantial of which related to the Unbalanced Group Theorem.

[1]https://axiommath.ai/research/the-enormous-theorem-formalize...

Many many gaps had been found and patched (by humans) already over the last forty years.