Support

That's how the SEF router works. You are trying to simultaneously fulfil two competing requirements: a canonical menu structure AND Joomla's free-form menu structure. This is not possible UNLESS all Category menu items are sub-items of the Categories menu item and use the same aliases as the respective categories.

Let me illustrate by means of a counter-example.

Imagine the following ticket structure: Components (top category) / Joomla (first level category) / Example (second level category) / #1234 Some question (ticket).

Imagine the following menu structure:

Menu item #123: Category "Joomla", alias "my-Joomla"
Menu item #140: Categories (all ATS categories), alias "support"
Menu item #153: Category "Example", alias "my-example"
Menu item #200: Category "Components", alias "my-components"

You have clicked menu item #140. Your URL is /support.html. What is the correct URL for the Example category? Is it /support/components/joomla/example.html, /my-components/joomla/example.html, /my-joomla/example.html or /my-example.html? Which one of these URLs is the canonical URL to the category? Because we need to give the canonical link at all times to avoid SEF issues.

The answer is that there is no sane answer. If you are in menu item #140, generating the URL passes Itemid=140 to the Joomla SEF router so you might think that the URL should be created as /support/components/joomla/example.html. However, menu item 140 is the wrong menu item type (Categories instead of Category) so we need to find a more specific menu item. You might now think that surely menu item 153 must be the most specific. But no. Menu item 123 comes first so you get /my-joomla/example.html instead.

If you tried the same exercise by having clicked menu item 153 your browser URL would be /my-example.html BUT the canonical URL the category would link to would again be /my-joomla/example.html.

So how do you route ticket #1234? It gets really funny because our specificity scope now changed. There are no menu items for Ticket so we need to find the most specific menu item for its category ("Example"). That would be menu item 153 so the canonical URL to the ticket is /my-example/1234:some-question.html EVEN THOUGH the canonical URL to its parent category is /my-joomla/example.html.

What I described is not a bug! It's the only reasonable way to fulfil the two opposing requirements. On one hand we are trying to have a nested structure of categories leading to a ticket. On the other hand we have a menu item structure in Joomla which undermines structure. So we have to work with specificity rules which create weird results.

It gets even worse when the specificity rules lead to a menu item with a different menu item type (view) than the one intended. If the most specific menu item is in a different menu Joomla might not report it at all, leading us to pick a different menu item, falling back to the Categories menu item. What I mean is that if menu item 140 was under the Main Menu and items 123, 153 and 200 were under the Hidden menu everything I said to this point would not apply! Instead, the URLs to the example category would always be /support/components/joomla/example.html and the URL to the ticket would be /support/components/joomla/example/1234:some-question.html. The hidden menu items would be ignored because they do NOT belong to the Joomla menu used to render the page.

So the correct menu structure is having everything in the Hidden menu, in the same structure as the ticket system categories and with the same aliases. Anything else will create results that are correct in the context of what you ask Joomla to do but totally incorrect in the context of what you expect.

This is exactly why no other CMS or framework lets the user-visible menu item structure determine the URL structure. It's INSANITY.