Categories are broken after plugin use

Hello, We installed this plugin a year ago on a website. At first, no problem was detected. The website have total of 300+ categories (categories with subcategories, subcategories with subsubcategories, etc.). But since a few weeks, we starting to see some problems with the categories. It randomly changes the order on refresh on page/posts editors, some categories appear twice or more, some don’t appear. The problem is also present with a simple REST api query. More about the REST API, after installing the plugin, the query parameter “orderby” no longer works. Could you please take a look at this? Thank you.