It seems that 2.4.2 has no option from the UI to add/change a parent's page.
Steps To reproduce the problem :
- Create a space
- create a page in that space
The URL will be correct (the page will be within that space), but the page won't have a parent, and NO place to set that parent. the Parent field from Document Information is missing.
Another problem is that when creating the Page, XWiki doesn't set it's space as parent.