This issue has been generating a lot of attention, in the SMS mailing list, from mails I've received and within Microsoft itself.

I've been working with HP support and Microsoft to find a resolution and it now seems clear that this is not a bug with SMS, but rather the Windows Update engine (as the problem can also occur with WSUS or by visiting the Microsoft Update site and scanning for updates). This problem is also affecting machines within Microsoft itself.

I've been reading a lot of words about McAfee scanning being the cause of this, we have discounted this theory (as we can reproduce the problem on a machine with McAfee completely uninstalled)

So, due to the sheer numbers of people reporting this problem, we can be pretty sure that a fix will be along soon. I'm afraid I don't have a timeframe for this yet though.