Here is one of several similar cases I have encountered in NOF XII:
1- Maybe important: the site was created from another site through a template
2- In the site structure, a child node was originally called "Thank you - Merci"
3- In the site structure, I changed this child node name to "Thanks" instead of "Thank you - Merci"
4- In the published site, a page with the name "Thank_you_-_Merci.html" is still created in spite of the name change, while I was expecting a new page "Thanks.html" which is not created
5- The parent page now points correctly to the page "Thanks.html" which is now nonexistent. This causes a default in browsing
6- In the links assets "Thank_you_-_Merci" is still listed with a note (page missing) and "Thanks" is not listed

If I am not mistaken, this is a recurrent problem, since old links still remain. So far, when I catch the problem, I go and modify the child page name in the published site. But in a large site, this is error prone.
Any idea on how to fix this problem and also how to prevent it?