404 on Single Category menu (SEF only) for authenticated users - Super User works correctly

[LinaG]

Hello,

I have been investigating a strange issue for quite some time and I have finally managed to isolate it.

Environment
• Joomla 6.1.2
• jDownloads 4.1.4
• PHP 8.5.2
• Apache (PHP-FPM)
• SEF URLs enabled

The same behaviour has existed since Joomla 4 and also occurred on older Joomla versions.

Problem
I have a Single Category menu item pointing to a protected jDownloads category.

Menu structure:

Authority Management (Public)
└── Committee (Public)
    └── Reserved Area (Access: Committee)
         -> jDownloads - Single Category
The category itself has the same access level as the menu item.

Behaviour
As Super User:
• URL without SEF → OK
• URL with SEF → OK

As a normal authenticated user belonging to the required access level:
• URL without SEF (index.php?option=com_jdownloads&view=category&catid=18&Itemid=320) → OK
• URL with SEF → 404

The generated SEF URL is:
/authority-management/committee/reserved-area/category/18-committee.html

Joomla Debug
With Joomla Debug enabled, the exception is thrown in:
Joomla\CMS\Router\Router::parse()
before jDownloads is executed.

Important observations
• The user definitely has permission to access the category.
• Access is confirmed because the non-SEF URL works correctly.
• Hidden "List All Categories (Default)" menu item exists.
• Rebuilding menus and clearing cache did not help.
• Re-selecting the category in the menu item did not help.
• Changing the category alias did not help.
• There are no duplicate menu items pointing to this category.
• Parent menu items are Public.
• Only the Single Category menu item is restricted.

Additional information
I have two completely different websites showing exactly the same behaviour.
• One site was originally created years ago (Joomla 3 and later migrated).
• The other site was created directly in Joomla 4.
• Both are now running Joomla 6.1.2 with jDownloads 4.1.4.
• Both have the same problem.

Interestingly:
If I create another menu item in the same location using "Single Article" or "List All Categories - jDownloads" (same access level), everything works correctly with SEF enabled.

The problem only occurs when the menu type is jDownloads -> Single Category.

Question
Is this a known issue with the Single Category router when SEF URLs are enabled?

Could the router be falling back to a generic route like:
.../category/18-category-name.html
instead of resolving the existing menu Itemid?

Any guidance would be greatly appreciated.

Thank you.
Lina

[Arno]

Hi Lina,
thank you for bringing this to our attention.

We are already working on this router/SEF issue. It is important to us to find a solution that resolves the error without changing existing URLs or rendering old links invalid. As soon as we have a reliable, backwards-compatible implementation, we will post an update here.