You shouldn't be able to hold on to a plug that's gone a mile, let alone 25. I would think there's a lack of spark on the cold one. I would check the wires to the cool plug. It could be the boot isn't making a good contact with the plug, or the wire to the boot isn't making a good contact with the boot. You can test this by switching the wires to the plugs, if the problem follows the wire, check the wire. If it stays on the same cylinder, it could be a fuel issue on that side.
2007 RMK 700, 2008 RMK 600, 1995 AC Prowler 2-up, 1980? AC Cheetah