Actually, we do monitor this field on all the changes via MOB by ourselves, so if you see any alert about VMware Tools status it means that VMwareVMStats.guestHeartbeatStatus has changed. Basically, there is no need in doing it by yourself (refreshing the page), you were advised to do that just to prove that we do not generate this alert about VMware Tools Status, cause we just inform you upon everything we get through VMware API by means of our Management Pack.
Generally, if you see this alert for only specifc VMs you may try to find what's in common between them, on the other hand if you see these alerts for random VMs, I also believe that VMware could give you more information on that and shed some light on the strange Tools behaviour.
By the way, what version of MP are you currently using? I'm asking this, cause we've increased the correlation Interval for VMware Tools Heartbeat in our latest update - Version 5.0.3 Build 248.