Page disappearing from the front-end

I encountered a weird situation...
Some of my pages simply disappeared form the front-end after publishing the website...

Example with https://www.pmdeclavieres.fr/adolescence/

Page exists in back-end :
https://i.imgur.com/dElUJL3.png

Page is published and slug is ok
https://i.imgur.com/gvVguAR.png

Front-end is 404
https://i.imgur.com/jNM9y8v.png

Page displayed in search results
https://i.imgur.com/vJQ1gmp.png

I had to change the slug to make the page appeared
https://i.imgur.com/UeEqcbD.png