Domain Controller (08R2) running as a Hyper-V machine, time is always ahead 10 mins?

I have 2 DCs.

Domain Controller (08R2) running as a Hyper-V machine, time is always ahead 10 mins.

I have done some steps to set the DCs to synchronize with the external time source time.windows.com

But , on the one DC, run

C:\>w32tm /query /source

return: VM IC Time Synchronization Provider

On the other DC, run  C:\>w32tm /query /source

return:  time.Windows.com

And on any oneof thetwo DCs,  run w32tm /resync /rediscover

time can be adjust to right, BUT after 1 or 2 seconds, yes , very fast,  time will automaticlly go ahead 10 mins in a flash!

What is wrong?