Caching.
It's always caching. https://shouldiblamecaching.com/ That explains why you don't immediately see the newest questions list in its most final version. (If you keep that page open in another tab while you post a new question, you will see a little "(1)" appear which, when you click on it, shows your question as the newest one.)
Is the question sent to moderator approval first, and then it will appear?
No.
Sometimes I found a quick edit and quick answer by people above 50k reputation even when the question appears after 2-3 minutes.
Maybe those people were keeping the question list open so that they could immediately spot updates to it?
The above images show how the tab appears with the "(1)", and how it looks on the front page of the site if you've kept that tab open.