Um, definitely not noticed that one Graham... I do find the puck needs a firmer knock to dislodge from the VST basket than my old Synesso baskets, which at least means you know there's a good seal between puck and walls -> no peripheral channelling. But the only 'mess' I've had has been limited to some coffee left behind in the basket which needs a quick wipe to remove, nothing ... er... explosive. Sure the kids haven't chucked some firecrackers in your knockbox??