Why change system time on test agent result TC task hang?

Folks,

I met a problem when implementing my TC setup. My case is below:

1. Setup TC web server on machine A, schedule test there
2. Having machine B as buildAgent, which will run my test there as well
3. On machine B(buildAgent), the test will change system time to some future time.
4. On machineA, I see the test I kicked off hangs on the test of step 3, which never quit

Is this a known limitation of TC?

Thanks,
Raymond