I have been upgrading my sites to PHP8 and fixing issues caught/cause by that. One of the issues was related to the plugin MB Custom Post Types & Custom Taxonomies, specifically by my taxonomy called media-kit-category. That was strange because all the setting were the same as my other taxonomies. After looking at the PHP code, I found that the last line looked like this:
I also do not see that issue on my demo site when getting the PHP code. Please make sure that you have the latest version of the MB Custom Post Type & Custom Taxonomy plugin v2.3.3 then recheck this issue.