When I create a new menu item using K2>category and select a category under Options>Select categories, the menu link is only index.php?option=com_k2&view=itemlist&layout=category. In other words, it's not linked to a category. Once upon a time, this feature worked (the links looked like index.php?option=com_k2&view=itemlist&layout=category&task=category&id=7), but now if I copy one of the working menu items and attempt to change the selected categories, nothing changes - the original category is still there.

And I've checked the permissions.

The template doesn't matter, and I've reinstalled K2. Any idea what I've broken? My main menu is all based on categories.

Hello Leslie,

Which version of Joomla! and K2 are you using?

K2 ver 2.8.0, Joomla 3.7.5

I have no idea what I did, but it's working again. Now it's just adding random images to items.

Clear both your browser's and Joomla!'s cache.
If the issue persists let me know.