Steve’s correct, it is a multisite issue. I did some checking, and WP multisite has an option to control whether that category slug field is displayed. There’s also a filter hook that can override the option
Here’s the source documentation:
https://developer.www.ads-software.com/reference/functions/global_terms_enabled/
So for your site, if the global_terms_enabled site option was set the network admin could unset that option by adding this code to a network activated plugin:
update_site_option('global_terms_enabled', false);
The code only should be run once, so it needs to be removed after executing. (e.g. add the code to the Hello Dolly plugin, activate the plugin, then deactivate it.)
However, there is a filter hook that can override this. Since you mentioned that disabling the plugins didn’t help, it’s unlikely that’s what’s happening here. But if there were a filter function in place, adding this code to an activated plugin would restore the option:
add_filter(
'global_terms_enabled',
'__return_false',
11
);
-
This reply was modified 6 years, 6 months ago by
Josh Feck. Reason: added priority to filter function