As mentioned previously, I don't know if that stator (no.3) died for the same reason as the other ones, but if the fault is electrical, it appears it comes from the connection between the end of the stator wiring and the external wires, and if it would be overheating I would assume that the wiring should be turning black all around the stator, not only one side !!
Because if you look at the 2 following pictures you see that the wiring is ok on the outside side, and starting to chip on the inside side. So it appears that the heat is coming from the flywheel. (and thus not from the exhaust either)
here is the picture from the outside side, the side facing the cover.