selected course categories keeps removing itself from courses

under "course overview / course setup" i would select a category for a course and it keeps removing itself.
by "removing itself" i mean it would not appear in the category widget or on the page for that category.
when i check back in the course setup, no category is selected.

this mostly happens i believe if i make any other change in course overview.
i am using Kleo theme, WP multisite, locally on MAMP Pro.
very frustration as i have to keep re selecting and saving while trying to build out a course.

could you please ask the developers to look into this ?

kind regards,