Hi J.
We noticed that when scanner 4 was down for maintenance the status page stated that the spam defs were only a couple of minutes old. So as you suggested, the closck of that scanner was behind, not the 14 hours the status page indicated the spam updates where old, but one hour behind. Updating the time on that scanner via the SBG GUI fixed it, the stauspage now states that the updates are 2 minutes old and I am smiling again :)
Thanks