Group Roles are not Inherited by Group Members on Import
This is the expected and normal behavior for XML Imports in ServiceNow.
The Business Rules which would normally process and update all of the users' roles do not run as mentioned here:
This can be fixed for all of the affected users by going to the Group Role, and unchecking and rechecking the Inherits checkbox.
Once that is performed, all of the necessary logic will execute and the roles will be provided for all of the group members.
To do so, follow the steps below:
1. Navigate to User Administration > Groups
2. In the Name column, search for the affected group and go to the record
3. In the "Roles" Related List, open the record for the missing role
4. Uncheck the "Inherits" field and save the form
5. Check the "Inherits" field back and save the form
All logic will now process and all group users will now inherit the role.