Disk latency reporting error in vSphere 5

On some of our disk performance graphs I am seeing the highest latency metric recording almost 200 million milliseconds.  That equates to over 50 hour latency spikes.  The storage isn't reporting any significant latency.  The vSphere client shows these latency spikes on the VM's datastore and disk performance graphs but not for the virtual disk.   The host is showing 6 second maximum command latency but nothing else above 50 ms.

Could this be a VAAI primitive issue?  Simple performance metric calculation error?

Thanks,

Chris