Exchange 2013 CU2 upgrade AD error

In my development environment, which is an exact replica of production, I am testing the upgrade for Exchange 2013 to CU2. When running the install all the prereq checks pass just fine, however once it begins to actually install I get the following error:

Error:
The following error was generated when "$error.Clear();
      install-AdministrativeGroup -DomainController $RoleDomainController

" was run: "Active Directory operation failed on "domain controller". The object 'CN=Folder Hierarchies,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN="domain",CN=Microsoft Exchange,CN=Services,CN=Configuration,DC="domain",DC=com' already exists.".

My thinking on this is, well of course it already exists, as this is simply an upgrade of the current Exchange 2013 CU1 (Version 15, Build 620.29). However this causes the installation to fail.

I have attempted to manually do the ADSCHEMA and ADPREP upgrades before running the software upgrade and both run with out error, however the software upgrade still fails.

Google hasn't found much on this particular error so I am wondering if anyone has any thoughts.

Thanks in advance!