Best Practice states 'Ensure all SEP clients and SEPMs are running the latest Maintenance Release"
http://www.symantec.com/business/support/index?page=content&id=TECH92051&locale=en_US
There have been many fixes since RU5, it may be worth your time to upgrade your manager.
BTW, look for MP2 to be released in the next 1 - 3 months.