TFS Build Schedule unstable?

[HarryZheng]

I have scheduled a build to start every Thursday at 7:00PM. It didn't start last week. In fact I scheduled before Thursday and that should have given it enough time to start at 7:00PM.

So I manually started the build and thought it would then reschedule the next build to this Thursday. Surprised I received an email telling me the build was successful as of last night (Tuesday). Now if it behavours like this, how can I trust it will do the job on Thursday or not.