[constantcrying]

>So how do you even fix a problem like this?

Slow down production, increase oversight and focus on training. Make sure that many employees stay for a long time and that they are encouraged to share their knowledge with new hires.

[CaptainOfCoit]

Also: (re) foster an environment where people can highlight issues without being ignored or even harassed for it. Once people start noticing that their reports about potential issues are ignored or makes colleagues act differently towards them, it's game over.