Hi Russell,
Thank you for letting us know. To begin troubleshooting, kindly identify your product version number and build number(login as default Admin and click on the license link, on the top right corner).
If the product build is lesser than 6380, then upgrade to the latest build by following the instructions on the link given below.
Once you have upgraded, kindly go to domain settings --> refresh --> Check "Users, Computers, & Dashboard View, Groups and OUs [Organizational Units]" --> Click on Ok.
Wait for a few minutes to complete the refresh and check for the issue.