A new hotfix for FIM 2010 R2 was relased, which mainly corrects the issue with Password Change Notification Service (PCNS) on Windows Server 2012 R2 Domain Controllers.
See: https://support.microsoft.com/en-us/kb/3048056/ for details and dont forget to check the “Known Issues” section if you have issues with custom MAs (ECMA) after applying the hotfix.
The release notes also showing the following hint:
Note In all supported cases, the FIM Synchronization Service must be installed only on a Windows Server 2008, Windows Server 2008 R2, or Windows Server 2012 member server. It must not be installed on a Windows Server 2012 R2 member server. Only the PCNS component can be installed on a Windows Server 2012 R2 domain controller.
You can download the hotfix here.