Windows MDT 6.3.8456.1000 Monitoring function doesn't work correctly

Server: Windows 2012  R2 Standard:

MDT: 6.3.8456.1000

After upgrading to 8456,  The elapsed time under Monitoring seems always incorrect. Please see me attached screenshot. I spent about 20 mins on deploying an OS, but it showed 10 seconds in MDT monitoring.