Yes, the curse of knowledge. The new person only has industry jargon that everyone else will have and so they will describe any new concepts that way instead of with the circular logic the team has established. And that is often something I have to explain to the new person when they look dubious at the notion that they have any right to be touching the docs at all. They have more right than just about anyone.

It takes a really good teacher to be able to explain as easily to an intern as to a principal, and often the intermediate people have to take the beginners aside and reframe your explanations anyway. Whether you witness it happen or they do it where you cannot see, it happens.

I also repeat the process with people that I'm responsible for onboarding. But it becomes my responsibility to compliment their contributions to the project in those early days so that it quells their nervousness about me tapping the brakes on their Bias Toward Action.

This is action, just not action that can tarnish both of us by shipping bugs to production.

Edit to add: I used to take ex coworkers out for coffee or beers around their last day and ask for a rundown of all the reasons they left. What you generally find if you let them keep talking is that they will run through the problems in reverse chronological order. The last thing they will mention is almost always what a joke the onboarding process was.

Last straws are the most recent thing that set the person off. All the straws before it add up, and if a person is already questioning the maturity of the organization on day 2 on the team, then I believe that multiplies your turnover rate. The longer you can go before a new employee says "what the actual fuck", is a multiplier on how long they will stick around.

Effectively, I think "the first 100 days" rule of thumb goes both ways. You get 100 days to show you're useful as an employee, but everyone already on the team is being held to the same yardstick by new employees. And if you're hiring at a high enough rate, having 20% of the team think the old employees are a waste of oxygen is not good for consensus building.