Read my post above. Mugabi was doing fine in the centre of the back three, as was McGinn at the right of the back three. But, to accommodate Butcher, who has been poor for a while now, both had to switch, which unsettled the defence. Blaney should've been on at that point to keep it settled, be he shit or not. The rot set in with that defensive change anyway, so the rest is ultimately inconsequential.