Hi.
Creating a Joomla menu link to the category gives the same behaviour (I had to give the link a different alias ofc).
I've double cheched the layout for the category-settings and they are the same as for other categories that work.
But disabling SEF made it work!
Obvously I want SEF enabled, but its nice to see something happen!

Anything in particular that made you suspect the SEF-functionality?