After upgrading my vCenter appliance 5.1 to 5.5 I noticed the following warning message at one of my 5.1 hosts:
Configuration issues. "Quick stats on hostname.domain.local is not up-to-date"
This is a known issue in vCenter Server 5.5.
To work around this issue, add these quickStats parameters to the Advanced Settings of the vCenter Server:
After I restarted the vCenter services the message disappeared
More information: VMware