I used to have a page with the slug /index/ and dozens of subpages beneath that one. Up until recently, all these pages worked fine. Now, all those subpages are returning a 404. I tried disabling all plugins and confirming that my
wp-config.php files hadn't changed, but the error persisted.
Renaming /index/ to /catalog/ fixed the problem, but now I have plenty of broken links pointing to the old URL structure.
Any idea what caused this problem to suddenly arise, and how I might resolve it so that I can use /index/ again? Or is this an inbuilt conflict with WordPress's own index.php?