Symptoms:
VMware vRealize Operations 8.x
VMware Aria Operations 8.x
This is as per design where vIDM user/user-group synchronization is not implemented as such as of its initial implementation and so far there was no requirement to add such synchronization.
To verify which Users/User Groups are getting access to VMware Aria Operations through user group imported from vIDM, check the members of that group from Active Directory.
Ensure that each user and group(s) must have a unique account with one or more roles assigned to enforce role-based security when they use VMware Aria Operations.