This happened today to a poor chap with a R26. Suspect wires may have been touching engine and insulation melted and caused this. Might be worth checking yours ....
One of the reasons I don't have the cover on mine so I can see things. That and they get pretty hot under them.
Checked a friend's car on friday at trackday and he had wiring hanging down and touching engine which if not checked could have led to the failure shown above
