It isn’t making mistakes that is actionable, it is failing to learn from them and repeating them.
Four people recently taken out of a special unit of a filming project not only couldn’t apply tech standardly on which they were fully hatted but also couldn’t learn from their mistakes. As a consequence their redone work contained the same mistakes that were originally made.
A new piece of Esto tech has come into view, those who cannot be hatted also don’t learn from their own mistakes and where you have this in a production unit it is better to replace the person rather than just hope.