To be clear the wiring to the ballast resister appears to be in good condition, it was the ceramic portion of the ballast resister that was brittle and broke apart with little effort.
That is usually a good thing. Those resistors are tough and rarely crumble but that is much better than a burnt wire.
Good possibility it got hit and cracked while somebody was working on something under the hood. Still check the coil resistance to be sure it isn't drawing too much current. Very doubtful it would cause a problem with the resistor even if it was shorting but better safe than sorry.
