Might be a little off base here, but possibly due to the high volume of updating that is currently going on, it is possible that the servers carrying the updates may be experiencing "traffic delays" Possibly an update package did not complete fully or was short a few bits, and there fore would produce an error message.
When you popped back on, perhaps the package was corrected, and that is why everything seemed to work.
Just a guess, but I myself did experience such a slowdown. Seemed to work itself out.