An issue has arisen on a Drupal site in our infrastructure which is very strange.
The site is running on Drupal and uses nice-menus to generate drop downs. The set-up is standard with a primary links menu displayed in the menu block. All was well and the menu was working fine for years.
The menu still works however now all child items are generated without titles or content. The menu links/href themselves are there and the menu can be clicked on but the menu items have no titles. I have checked the php logs and no errors are being thrown. I also verified with some error_log() calls and the titles are indeed missing in the generated menu arrays.
But here's the strange thing, it works fine when logged into the site as an administrator but not as an anonymous user or an authenticated non-administrative user. But I have confirmed the menu is configured to allow access to all user roles. I have also cleared all caches multiple times.
I did some further digging and if I change the internal Drupal urls of the menu items e.g. node/5 etc. to their external urls, the menu works fine again.
I'm really hoping someone has seen this before since I can find nothing relating specifically to this issue in almost a day of searching. I'd appreciate the input.