Coil resistance

[Fazerider]

Have you trimmed the leads? The end bit where the plug cap screws in gets damaged which is why you eventually need to chop a centimetre off to get contact with some good copper.
If there's a break you'll get no continuity when you do the resistance check, but the coil can still generate enough volts to jump the gap. The trouble is it reaches a higher voltage in order to do so, hence it either starts tracking down the outside of the plug cap or breaks down the insulation internally and causes a short in the coil itself.