Does network time not sync properly when proxy server is used?

Normally, one can compute the appoximate time elapsed since an RPC call was made by subtracting the RPC timesamp from Network.time. Like so:

 @RPC
 function PrintTimeDelta (info : NetworkMessageInfo)
 {
  Debug.Log("Time Delta = " + (Network.time - info.timestamp).ToString() + " (Network.time: " + Network.time + " - timestamp: " + info.timestamp + ")");
 }

This works great when not connected through a proxy:

Time Delta = 0.00799999991431832 (Network.time: 827780.803 - timestamp: 827780.795)

But with a proxy, I get something like this:

Time Delta = 819249.191 (Network.time: 828000.764 - timestamp: 8751.573)

Looks like the remote time doesn't get translated into local time correctly. Is this a well known bug/issue, or something I'm doing wrong somewhere? Any work arounds?

Thanks, Mark