Win Clock synch issue

Using 10.5.2, Win XP Prof SP2, when my Mac Pro wakes up from sleep, its clock catches up immediately but my VMs clock does not. It remains at the time it did when the computer fell asleep. The time synchronization option is enabled within Parallels Tools Center. I've unchecked it, rebooted, etc but no luck. I operate the VM in 'full window' mode all the time on a second screen...if that matters...

Is this a possible bug?