Categories bug

I just downloaded version 3.4. The booking time bug is fixed, however I have encountered another one. When I assign services under a certain category, the services do not display when I attempt to expand the list of services under a specific category. I just does nothing. I have a variety of services, and this organization is key to keep the user experience as simplistic as possible.

https://ww.wp.xz.cn/plugins/salon-booking-system/