Including the category group in nested category URIs? I've asked already about nested categories here, but I've just upgraded to Craft 3 and things seem to have changed a little.

I have three top-level category groups:

- Home
- About
- Funding


Each of these has multiple categories, and some of these categories are nested up to three levels deep.

My problem: the nested category URIs don't include the category group (which I appreciate doesn't have its own slug). Instead I get stuff like this:

/cat-A/subcat-1/
/cat-B/subcat-2/subcat-6/


... when what I want is:

about/cat-A/subcat-1/
funding/cat-B/subcat-2/subcat-6/


If I manually add funding/ or about/ as part of those categories' URI formats (eg. funding/{parent.uri}/{slug}) then it appends funding/ at each level, eg: funding/funding/funding/cat-B/subcat-2/subcat-6. 

I've managed to achieve what I want for entries, by setting their URI format like so: 

{category.first().group.handle}/{category.last().uri}/{parent.uri}/{slug}


... which gives me stuff like:

funding/cat-B/subcat-2/subcat-6/entry-title-slug


I only really need this feature to work because I envision users browsing the categories and potentially clicking the URI/links and being taken to the wrong place.

In my earlier post I created a top-level category group called "Navigation" which contained all my categories – this achieved the correct URIs. This feels messy/hacky though and means my users have to see a redundant "Navigation" group when editing categories.

It's likely I'm misunderstanding some aspect of Craft here – can anyone help me achieve what I'm trying to do here?
You would just enter { parent? parent.slug : '' }/{ slug } in the "Category URI Format" Field in the Craft3 CP and it will recognize nested categories