Accounts are created for computers, these will be created as COMPUTERNAME$
Actual users are created as an Account and added to the Symantec Administrator Role, potentially giving them more rights that expected or desired
There are two possible causes:
For computers being created as an account see TECH231057
For Users being created as accounts and added to the Symantec Administrators. There was a new feature added in 7.6 HF1 that will do this when a user is added to the local Administrator group on the Notification Server.